Arsene Wenger accused his Arsenal players of a lack of commitment during their lacklustre 2-1 defeat at struggling Queens Park Rangers.
Wenger's side came into the game on the back of a run of seven successive Premier League victories and had a chance to consolidate their position in third place.
Instead, the loss meant they failed to extend their three-point lead over fourth-placed Tottenham, who have a game in hand against Swansea on Sunday, while Chelsea's victory at Aston Villa reduced the gap between third and fifth spot to five points.
"Of course, it was a shock for us today and I felt sub-consciously something was missing," Gunners boss Wenger said.
"And in the Premier League if you miss something on the commitment front then you are beaten and that was the result of the game."
Third-bottom QPR remain locked in a relegation battle and Wenger admitted his side had been out-fought while also lacking the creativity to take advantage of their territorial dominance.
"It is very frustrating because they left us the ball and waited for our mistakes," Wenger said. "And we took the ball, didn't do a lot with it and made the mistakes. And at the end of the day that makes the result.
"I feel our performance was not good enough to win this kind of game, especially individuals they had that showed extra special commitment that took advantage of us in some specific positions defensively."
The home side capitalised on two mistakes by Arsenal centre back Thomas Vermaelen with Adel Taarabt opening the scoring in the 23rd minute and Samba Diakite netting the 66th minute winner after Theo Walcott had equalised.
But Wenger insists his side is still on course to claim a top four finish and, after suffering a number of setbacks already this season, he believes they know how to respond to this disappointment.
"At the end of the day we lost a game when our keeper has had nothing to do and it's not the first time this year we have been too open when we have lost the ball," he said.
"We know how to respond. We have been exposed many times to this kind of situation."
QPR manager Mark Hughes hailed the contribution of captain Joey Barton who was restored to the line-up after being dropped for the defeat at Sunderland.
Barton has been heavily criticised by the club's supporters in recent weeks, particularly in the recent win over Liverpool, and used his programme notes to admit the flak had affected his game.
But Hughes believes the midfielder provided the perfect response.
"I read the programme but it was a difficult night (against Liverpool) for Joey and he accepts that," Hughes said.
"He fronted up. He was man enough and put the shirt on and said 'this is what I am all about, this is what I can do on the football field', and I was really, really pleased for him."
Hughes was also impressed by Diakite who he believes is beginning to settle in the Premier League after signing from Nancy on loan in January.
"He came in and he was very green, didn't really know how the game was refereed and he has had to learn quickly. Thankfully he has," Hughes said.
The win means only goal difference separates Rangers from safety and Hughes added: "If we play like that, at that level from now until the end of the season, we will win more games.
"The teams around us weren't possibly playing the quality of opposition we were today and we were able to overcame them.
"They will have weekends where they have to come up against opposition like we had today and we will have to see how they do."
The only dark cloud for QPR was an incident late in the second half when a linesman appeared to be hit by an object thrown from the stands, opening up the possibility of an FA investigation.