Arsene Wenger accused Arsenal of naivety after they were pushed to the brink of another frustrating Champions League exit by Lionel Messi's brace in Barcelona's 2-0 win at the Emirates Stadium.
Wenger was infuriated his players failed to heed his warning to keep it tight at all costs in the last 16, first leg on Tuesday as Messi punished the hosts' careless defending with a clinical 71st-minute opener.
Messi then took advantage of a needless foul on him by Mathieu Flamini, stroking home the resulting penalty to leave Barca on the verge of reaching the quarter-finals for a ninth consecutive year.
It was a familiar tale of woe for the Gunners manager, who only this week had spoken publicly of his desire not to repeat the first-leg gung-ho tactics that had played a major role in Arsenal's five successive last-16 failures.
"Of course I'm disappointed. We lost it in a way we knew we could not give them," Wenger said.
"We were extremely guilty. It's very difficult to take. If we had to keep a 0-0 I would have been happy with that.
"They are better than us, everybody knows that, but we could have won the game if we had kept our discipline.
"We were impatient in the build up and lost balls we usually don't do.
"Once again, like against Monaco last season, we lost the game in exactly the same way. (It was) naive and that is frustrating. We just gave it away."
Wenger's anger was compounded because, for much of the match, he could have no complaints as Arsenal frustrated the European champions with a composed performance that could have yielded a lead if not for poor finishing.
"Barcelona master all aspects of the game and they have the players to punish you. But I felt there was room to beat them tonight. That is the frustration," Wenger said.
"We had an unbelievable chance in the first half and the way we finished was a problem.
"Then we lost a bit of cautiousness to defend. When you leave a counter-attack that is when Barcelona is most dangerous."
Now Wenger is left to survey the wreckage of Arsenal's latest European flop and he conceded there was virtually no chance of a miraculous escape in the second leg in Spain on March 16.
"Barcelona is 95 percent through certainly, but we want to go there and fight," added Wenger, who was less than impressed with the way the visitors often made a meal of their response to tough tackles.
"Not one goes down without shouting," he moaned. "I felt the referee was influenced but let's be honest, we didn't lose the game because of the referee."
Barcelona defender Gerard Pique will miss the second leg after a late booking which followed a touchline chat with boss Luis Enrique, prompting suggestions it was a deliberate move to get a ban out of the way before the last eight with the tie effectively over.
But Luis Enrique denied that charge, saying: "No, it wasn't deliberate. if you see the foul, obviously he has to do it."
The coach was much more comfortable discussing his majestic side's 33rd consecutive unbeaten match.
"We managed to deal with Arsenal's pressure really well. We are one of the best clubs in the world when it comes to dealing with a tight defence," he said.
"We have had a really high defensive level. Arsenal had players to do us a lot of harm, but we were up to the challenge of all the dangers they could present us."
Few would bet against Barca winning their sixth European Cup this season, but Luis Enrique refused to write off Arsenal yet.
"The score is really good but nothing is decided yet. We will have to play really well in front of our own crowd to go through," he said.
Lionel Messi proved a thorn in Arsenal's side yet again as his late second-half goals, including a penalty, gave Barcelona a 2-0 win at The Emirates in the first leg of their Champions League last 16 tie on Tuesday.
The Spanish holders' feared attack had been well shackled by a disciplined home side for much of the evening, but a lightning break after 71 minutes saw Argentine Messi teed up by Neymar to score past keeper Petr Cech for the first time in his career.
Messi, who netted four goals against the Gunners in 2010 and a double a year later in knockout round wins, doubled Barca's lead seven minutes from time when he beat Cech with a penalty, having been tripped by Arsenal substitute Mathieu Flamini.
Arsenal relied on counter-attacks and had chances, most notably from Alex Oxlade-Chamberlain and Olivier Giroud, but now have a daunting task to turn the tie around in the Nou Camp.
Barca's frontline of Luis Suarez, Messi and Neymar had scored 91 goals in all competitions this season but for the first 20 minutes they were subdued in an electric atmosphere.
Arsenal should have taken the lead midway through the first half when Hector Bellerin's scuffed shot fell for Alex Oxlade-Chamberlain in front of goal but he scooped his effort straight at goalkeeper Marc-Andre ter Stegen.
The Catalans began to move through the gears though and either side of halftime wasted two glorious chances.
Suarez headed Dani Alves's dinked cross wide when he should have scored at the end of the opening period and Neymar was denied by Cech after being played in by Andres Iniesta.
Starved of the ball for long periods, Arsenal still posed a threat though and Ter Stegen did well to keep out Olivier Giroud's close-range header from a Mesut Ozil cross.
Arsenal grew in belief but it cost them dear as they committed players forward and got stung.
With 19 minutes left Suarez and Neymar combined in devastating fashion and the Brazilian set up Messi who steadied himself and picked his spot to beat Cech.
Suarez then hit the post when he should have scored before Messi struck again, this time with a calmly struck penalty.
Arsenal 0 Barcelona 2 (Messi 71" 83")
90" Three minutes of injury time added.
85" YELLOW! Gerard Pique is booked for a lunging tackle on Welbeck and will miss the next match.
Arsenal 0 Barcelona 2 (Messi 71" 83")
83" GOAL! Substitute Mathieu Flamini brings down Messi and the ref points to the dreaded spot. Messi scores sending Cech the wrong way
81" Flamini in for Coquelin.
78" Ramsey comes close, getting his toe to a header from Welbeck but Ter Stegen narrows the gap.
77" Suarez misses a sitter finding the post from close after Neymar first had a chance.
73" Danny Welbeck, on for Olivier Giroud, races into the penalty area but his cross is blocked and the chance is gone.
Arsenal 0 Barcelona 1 (Messi 71")
71" GOAL! The trio are at work. Neymar begins the move from his own half and finds Suarez on the left. The Uruguayan in turn back passes to the Brazilian who by then had covered a lot of ground. Charging with the ball into the Arsenal box Neymar crosses for Messi who deceives Cech with a slight feint and chips it into the net. Briliant stuff.
67" The action has definitely picked up and Giroud is left unmarked with the ball. Instead of going it alone he tries to find his teammate and makes a mess of it.
64" Arsenal forge ahead with Sanchez and Ramsey having a crack only to be denied. Elsewhere Messi finds his bullet-like left footer crash into a defender and Neymar fails to meet Suarez's cross which goes tantalisingly close across the goal..
61" Messi tries to bamboozle past Monreal -- only manages a corner.
59" Barca goalkeeper Marc-AndreTer Stegen is brought into the picture for the first time and makes his presence felt with a brilliant save to deny Giroud what looked like a certain goal.
53" Messi and Neymar work in tandem to put pressure on Arsenal which is showing signs of crumbling. It's a matter of time now.
49" Chamberlain is replaced by Theo Walcott.
48" Neymar makes a superb run from an Iniesta through ball but Cech charges out and stretches his right leg to deny the Brazilian from hand-shaking distance.
45" No changes made to the two sides.
Arsenal 0 Barcelona 0
Barring that close call from Suarez, Arsenal did well to keep Barcelona quiet and also come up with a few of their own threats.
45" Long ball from Jordi Alba and Dani Alves volleys it back for unmarked Suarez. The Uruguayan was in front of goal but heads wide and later holds his head in his hand. That was the closest in this half and could prove coxtly too.
43" Neymar tries valiantly to make some inroads and so does Suarez but the Arsenal defence is standing tall. How long can they do that is a question?
40" Lot of passing between the Barca players but they are finding it tough to break through the Arsenal cordon.
35" Arsenal break free after Messi messes his free-kick from just outside the Arsenal box. Chamberlain makes a darting run but Mascherano's timely tackle leaves both players writing in pain.
32" Suarez gets into action after Neymar sets him through but Cech dives full stretch. The ball goes over the touchline and Suarez appeals for a corner which is turned down.
29" Finally Messi makes one of his trademark runs but Francis Coquelin pulls him down by the sleeve and is punished.
27" Arsenal have come into their own as Barca's trio are kept quiet.
25" Alexis Sanchez's diving run fetches a corner but Ozil's shot is cleared by Suarez.
22" Oh no...Chamberlain almost put the hosts ahead. After a good move from him which culminated with Ozil and Ramsey too getting involved the ball fell at Chamberlain's foot in the penalty area and from the scarmble with Pique and Mascherano he managed a weak shot but it was directed straight at goalkeeper Ter Stegen.
18" Barca have started to camp in the Arsenal half and that could be dangerous but Wenger's boys are capable of catching Pique and Alves on the wrong foot from a counter attack.
16" Barca show good ball control and passing as Iniesta moves into the Arsenal box but ends up with a futile shot.
13" Ivan Rakitic tries an ineffective long range but earns a corner which is cleared by Oxlade-Chamberlain..
11" Arsenal get a free kick from 30 yards out but Ter Stegen charges out for an easy collection.
7" Mesut does well to catch the Barca defence unawares as he enters the penalty area, but his back pass catches Ramsey on the wrong foot, his left, and the chance is snuffed out.
5" YELLOW! Nacho Monreal earns an early booking although a bit harsh after he lost his footing and ran into Rakitic.
3" Neymar has his first taste of the ball but is brought down by Aaron Ramsey who is warned by Turkish ref Cuneyt Cakir.
1" Arsenal have pressed early with a long ball for Giroud and earn a throw in the Barca zone. Giroud and Sanchez take pot shots but they richochet off defenders.
The moment that everyone is waiting for has finally arrived. The two teams are in the dugout and the kick-off is just five minutes away.
The 'Big Three' of Messi, Neymar and Suarez make their way into the middle for some light training and they are greeted with loud cheers from the travelling Barca fans.
We are half an hour away from kick-off so if you've not had your dinner then do so and get ready to plonk yourself in front of your TV to watch the best strike force of Messi, Neymar and Suarez.
No surprises there from both teams as news pour in that Mesut Ozil, Aaron Ramsey, Olivier Giroud, Alexis Sanchez and goalkeeper Petr Cech are back for Arsenal after being rested against Hull in the FA Cup match.
As expected Barcelona too have gone in with a strong outfit in Messi, Neymar and Suarez. Busquets and Pique return after missing the match against Las Palmas.
Hello and welcome to what promises to be a scintillating night of Champions League football between Barcelona and Arsenal at the Emirates Stadium.
Arsenal XI: Petr Cech, Hector Bellerin, Per Mertesacker, Laurenct Koscielny, Nacho Monreal, Francis Coquelin, Aaron Ramsey, Alex Oxlade-Chamberlain, Mesut Ozil, Alexis Sanchez, Olivier Giroud.
Barcelona XI: Ter Stegen, Dani Alves, Gerard Pique, Javier Mascherano, Jordi Alba, Sergio Busquets, Ivan Rakitic, Andres Iniesta, Luis Suarez, Lionel Messi, Neymar.
Arsenal are third in the Premier League on 51 points, same as Tottenham and two behind Leicester City.
The Gunners haven't reached the quarter finals stage of the Champions League for six years.
Barca are top with 63 points in La Liga
Barcelona are undefeated in their last 7 matches (UEFA Champions League).
Barcelona are 32 games unbeaten in all competitions.
Neymar, Lionel Messi and Luis Suarez have scored 81 goals across all competitions this season
Barcelona coach Luis Enrique will wave his wand over the 'Chosen Ones' - Lionel Messi, Luis Suarez and Neymar - to make sure they weave their magic at Arsenal in the Champions League last-16, first leg on Tuesday.
Asked what he does to get the best out of the trio, arguably the most dangerous forward line in world football, the former Barca midfielder joked that they made his job fairly easy.
"I tell them 'abracadabra' and the magic sparks, that's all I do," Luis Enrique told a news conference on Monday with a laugh before getting more serious.
"To be honest I always work really hard but it's quite easy with them because in some situations in a game you don't have to wish what they do because they already do it."
Barca, bidding to become the first team to retain the European Cup since AC Milan achieved the feat 26 years ago, take a 32-match unbeaten run into the first leg at the Emirates.
Argentine Messi (15 goals), Uruguayan Suarez (25) and Brazilian Neymar (18) have scored a combined 58 times in La Liga to put Barca eight points clear at the top.
Luis Enrique, however, is just as keen for them to show off their defensive attributes against Arsenal.
"They are the 'Chosen Ones' because they are fantastic and always eager to win," said the former Barca midfielder.
"We also depend on the pressure they put on up front to get the ball off the opposition."
While many top European teams rotate their strikers, Messi, Suarez and Neymar are rarely given a breather by Barcelona.
"They never rest, or stop playing, but if they didn't play they wouldn't like it that much," said midfielder Ivan Rakitic.
"They are like children when they play football. It would be like taking the ball away from them if we didn't choose them. Those three make us a better team."