Michael Carrick's first Champions League goal in three years gave Manchester United an unconvincing 1-0 victory over Galatasaray and a winning start to their Group H campaign at Old Trafford on Wednesday.
England midfielder Carrick finished a neat move by rounding keeper Fernando Muslera and coolly slotting home in the seventh minute.
But United could not build on their lead and Galatasaray, appearing in the Champions League for the first time in six years, were unlucky not to get a point after hitting the woodwork three times through Nordin Amrabat, Hamit Altintop and Selcuk Inan.
Nani made United sweat for the win when Muslera saved the Portuguese winger's feeble 53rd-minute penalty following a foul on Brazilian defender Rafael.
Alex Ferguson's side failed to reach the Champions League knockout rounds last season - the first time since 2005-06 they had fallen at the group stage - and they won just one game at Old Trafford in dismal Champions and Europa League campaigns.
The overriding emotion afterwards was one of relief at the result rather than concern at the performance.
"Three points in the opening game are very important, especially when you look at what happened to us last season," Ferguson, who celebrated his 100th Champions League win, told reporters.
"In the first half we gave the ball away too often and they counter-attacked really well. In the second half, we were much more solid at the back, and all the chances fell to us.
"It was a good opening game, they were very confident in their possession, and missing the chances we did in the second half we kept ourselves on the edge."
Ferguson had made a point of challenging his players to eradicate their complacency and defensive vulnerability but the players nearly embarrassed their manager after one minute.
Captain Nemanja Vidic was fortunate not to concede a penalty when he tripped Galatasaray striker Umut Bulut and referee Wolfgang Stark waved play on.
It seemed the home side had shaken off nerves when Carrick provided the breakthrough for the three-times European champions.
The midfielder exchanged incisive passes with Robin van Persie and Shinji Kagawa before taking on Muslera in a one-on-one, but even though the keeper clipped Carrick's heels, he kept his composure as he lost his balance to slide in the finish.
"I don't get many, so when the chance is there," Carrick told Sky Sports. "You can go down, and there's a chance the keeper will be sent off, but we've missed three penalties now (this season), so taking the chance was the right one."
The goal, however, did little to deter the visitors, and United, could not exert control.
Galatasaray, working with a bold formation from coach Fatih Terim of two up front, forced United backwards and twice before the break went close to an equaliser.
Amrabat cut in from the left and bent a curling right-foot shot from 25 metres on to David de Gea's crossbar, and Altintop, the former Bayern Munich midfielder, ripped a low shot on to the base of the post.
Terim's side struck wood for the third time in the 56th minute when Inan flicked a header on to the outside of De Gea's right-hand upright.
By then United's frustration had increased with Nani's penalty miss.
Right back Rafael won the spot-kick, drawing a foul from Burak Yilmaz as he burst into the area eight minutes after halftime. But the Portuguese stuttered in his run-up and his weak effort was easily saved by Muslera.
Galatasaray came within millimetres of an equaliser again after 71 minutes.
The visitors broke quickly after a Nani penalty claim had been ignored, and De Gea palmed away Yilmaz's shot before brilliantly getting his fingertips to substitute Emre Colak's fizzing follow-up.
Darren Fletcher, out for 10 months with a chronic bowel condition, came on as a substitute to make his first United appearance since their Champions League draw with Benfica at Old Trafford last November.
Ferguson also introduced Javier Hernandez and Danny Welbeck in search of a second goal but even that would not have masked a mediocre night for the 2011 finalists.