After all the trials and tribulations of last season's humiliating Champions League campaign, Manchester United got this year's group stage off to a winning start, although this was a far from convincing performance against a Galatasaray side who were entitled to feel aggrieved they had nothing to show for their efforts.

It turned out to be a tense occasion for United and if anything summed their night up it was Nani's dreadful penalty kick, the winger's second-half effort easily saved by Fernando Muslera after he had stepped forward with a total lack of conviction, stopping in the middle of his run- up. United have now missed all three penalties this season – Robin van Persie and Javier Hernández are the other guilty men – and it was easy to imagine Sir Alex Ferguson's 'hairdryer' being put to use afterwards.

In the end United were grateful for Michael Carrick's wonderful early goal, which was the midfielder's first in the Champions League since he scored against Wolfsburg three years ago and proved to be enough to vanquish a Galatasaray side who played with attacking abandon throughout. Only the combination of David's de Gea's fine goalkeeping, some generous refereeing and a touch of misfortune in front of goal, prevented Fatih Terim's team from scoring.

United, wearing black armbands as a mark of respect to Fiona Bone and Nicola Hughes, the two policewomen killed during a gun and grenade attack in Manchester the previous day, were careless in possession, much to Ferguson's annoyance, and looked vulnerable whenever Galatasaray pushed forward. They were also highly fortunate to get away with what was a definite penalty inside the opening minute, when Nemanja Vidic upended Umut Bulut.

Wolfgang Stark, the German referee, waved play on and a collective sigh of relief swept around Old Trafford. When Carrick scored six minutes later it should have given a strong United side – Ferguson made six changes from the team that beat Wigan on Saturday – a platform to build on but they never looked comfortable and ended up muddling their way through a game that finished with relief as the overriding emotion.

Van Persie looked particularly out of sorts and when the Dutchman was booked in the closing stages it was no surprise when his number went up moments later. Darren Fletcher had come on just before and his late cameo provided one of the few positives for United.

The Scotland captain has been sidelined for 10 months with ulcerative colitis and there were fears that his career might be over. Fletcher received a huge ovation and, on this evidence, the energy he provides in central midfield will be much needed over the coming months.

Although United created chances – Nemanja Vidic, Nani and Patrice Evra all went close – they were opened up far too easily at the other end. The warning signs were there in the 10th minute, when Nordin Amrabat escaped on the Galatasaray left and cut inside before curling a right-foot shot that clipped the top of the crossbar.

By that point United were ahead through a beautiful goal that illustrated what a graceful player Carrick can be. Picking up possession deep in midfield, he played the ball into Van Persie's feet and continued his run, elegantly striding forward to receive it back from the Dutchman before swapping passes with Shinji Kagawa, slicing open the Galatasaray defence in the process, and leaving him one on one with Muslera.

Carrick swayed his hips and danced around the Galatasaray goalkeeper, admirably staying on his feet when he could have gone down, before planting the ball into an empty net.

Galatasaray, however, refused to be cowed. Hamit Altintop, whose powerful running was a striking feature all evening, clipped the outside of an upright from a well-worked free-kick towards the end of the first half. United should have put the game to bed early in the second period when Rafael da Silva, gliding forward from right-back, was brought down by Burak Yilmaz in an almost identical position to where Vidic fouled Bulut.

Nani placed the ball on the spot and thereafter it was a lesson in how not to take a penalty. He stuttered and telegraphed his intentions, shooting at a comfortable height nowhere near the corner.

Back came Galatasaray, Altintop delivering a centre that Selcuk Inan met with a glancing header that flashed past the far upright. Although United were enjoying a greater control of possession, there was always the danger that they would be caught by a Galatasaray counter-attack and so it proved in the 72nd minute, when the visitors broke with alacrity. If the first stop that De Gea made to deny Yilmaz was routine, the flying save that the Spaniard produced to turn Emre Colak's stinging left-footed effort behind was quite spectacular.