London: Wayne Rooney got Manchester United`s bid for a fourth consecutive Premier League title off to a winning start with the only goal in a 1-0 victory over promoted Birmingham City at Old Trafford on Sunday.
The England striker reacted quickly 12 minutes before halftime, stabbing in a rebound from close range after his initial header from Nani`s cross came back off the post.
It was far from vintage United, however, with Birmingham able to carve out chances, most notably when substitute Christian Benitez forced a fine save from Ben Foster late on.
Free transfer striker Michael Owen made his competitive debut for the champions, replacing Dimitar Berbatov with 15 minutes remaining.
Liverpool, who pushed United all the way last season, open their campaign against Tottenham Hotspur later on Sunday.
With much of the pre-season talk surrounding the loss of Cristiano Ronaldo, United`s most influential player during their recent domination of the league, all eyes were on new signing Antonio Valencia and Nani.
Valencia had a quiet debut and Nani was involved in United`s winner before being replaced at halftime by veteran Ryan Giggs, beginning his 18th Premier League campaign.
Owen nearly made an immediate impact, having one shot well saved by Joe Hart and another effort ruled out for offside.
"I started with Wayne and Dimitar because they have been at the club last season and were regulars but Michael will get his chances, no question about that," United manager Alex Ferguson told Sky Sports.
"There are plenty of games coming up in the next few weeks for him to take those chances."
United were dealt a blow when centre back Rio Ferdinand was ruled out with a calf injury and they often looked jittery at the back against a Birmingham side who gradually gained belief.
The early stages were all United with Rooney having one curler tipped over the bar and another effort blocked before he opened the scoring in the 33rd minute.
Nani found space out on the left and his cross was well met by Rooney with a firm header which hit the post and rebounded for the striker to tap in.
Birmingham have never scored a Premier League goal at Old Trafford but they came close before halftime when Franck Queudrue`s near post header was cleared off the line by United defender Patrice Evra.
Rooney was United`s main threat in the second half but they failed to kill off the visitors and suffered anxious moments late on as substitute Benitez impressed for Birmingham.