Cristiano Ronaldo scored a second-half header on his return to Sporting Lisbon to ensure Manchester United's Champions League campaign started with a victory.
Cristiano Ronaldo celebrates his winner for Man Utd in Lisbon
Ronaldo won warm applause from the home fans for his subdued response to converting Wes Brown's cross after 61 minutes of a low-key encounter.
Wayne Rooney made a quiet comeback after recovering from a broken foot.
And United were grateful to keeper Edwin van der Sar, who made superb saves from Liedson and Tonel.
Rooney, as expected, was restored to United's line-up for the first time since sustaining his injury in their opening Premier League fixture against Reading.
Carlos Tevez dropped down to the bench, but Rooney and Ronaldo fed on scraps in a first 45 minutes in which United seemed set on containment.
Van der Sar made a stunning save to keep them on level terms after 27 minutes, diving to save one-handed from Liedson's rising drive.
Nani, another United star returning to his former club, saw a shot deflected narrowly wide after 32 minutes, but then picked up a yellow card for a reckless challenge on Miguel Veloso.
Ronny audaciously tried his luck from 35 yards from the resulting free-kick, but Van der Sar saved comfortably.
Ronaldo started to influence affairs after the break, sending in a cross which was just too high for Ryan Giggs, who failed to control his header.
He made no mistake with his own headed opportunity as United took the lead after 61 minutes.
Brown was the creator with a fine right-wing cross, which Ronaldo diverted past Vladimir Stojkovic with a diving header.
Ronaldo's celebrations were muted as Sporting fans generously applauded his goal, against the club he left four years ago, aged 18.
Nani almost made it a double for United's former Sporting stars with a swerving long-range effort that Stojkovic palmed to safety with 20 minutes left.
It was the signal for Sir Alex Ferguson to withdraw Rooney, who had made a very quiet return after injury, with Louis Saha coming on.
Van der Sar had been excellent for United, and he showed his quality again when he turned away Tonel's header when it looked certain he would turn home Veloso's cross.
Ronaldo left to a standing ovation with four minutes left, but limping slightly, which will be a worry with Chelsea awaiting Manchester United this weekend.
United had been in control after the break, although Sporting substitute Simon Vukcevic shot narrowly wide late on.
Manchester United boss Sir Alex Ferguson:
"Winning your first game away from home sets the tone for us. At half-time we looked to improve our game with more penetration - I think we did.
"They had some opportunities on the edge of the box but never really opened us up.
"It was hard to know how long to keep Wayne Rooney on, but the goal made it easy."
Sporting: Stojkovic, Abel, Tonel, Anderson Polga, Ronny (Bruno Pereirinha 74), Izmailov (Vukcevic 55), Veloso, Joao Moutinho, Romagnoli (Purovic 67), Djalo, Liedson.
Subs Not Used: Tiago, Paredes, Farnerud, Gladstone.
Man Utd: Van der Sar, Brown, Ferdinand, Vidic, Evra, Carrick, Scholes, Nani, Giggs (Anderson 76), Ronaldo (Tevez 86), Rooney (Saha 72).
Subs Not Used: Kuszczak, Pique, Evans, Eagles.
Booked: Nani, Van der Sar.
Goals: Ronaldo 62.
Ref: Herbert Fandel (Germany).