De Gea looks back at the goal after failing to stop Long's shot
A late own goal spared goalkeeper David de Gea's blushes as Manchester United began their defence of the Premier League title with victory at West Brom.
Wayne Rooney scored early on when he combined with Fabio and Ashley Young to drill in a low effort.
Shane Long equalised on his competitive debut for West Brom when his tame effort crept under the body of De Gea.
United grabbed the winner when Young's cross from the left took a deflection off Steven Reid and beat Ben Foster.
Young claims winning goal
In the end luck was on the side of United, who had dominated for much of the first half but seemed devoid of bright ideas after the break.
Had Reid not put through his own net then De Gea's error would have been highlighted on Monday's back pages, although it is unlikely his moment to forget will pass without comment.
In the past Ferguson's Achilles heel has been the man wearing the number one jersey and on Sunday De Gea may have made his manager consider whether he was right to throw the 20-year-old straight into the first team.
Other young players such as Tom Cleverley and Danny Welbeck have been loaned out to gain experience before being handed their first-team opportunity, but Ferguson had no hesitation in giving the £18m summer signing his league debut.
Rooney opens the scoring early on
The Spanish stopper looked impressive when he took up a good position and then stayed on his feet to palm away a fierce strike from Paul Scharner. However, he appeared weak when balls were floated into the area.
Yet it was not a teasing cross that outfoxed De Gea for the West Brom goal but a weak strike that drifted under his body.
Up until the equaliser, United were in control and some fans must have been wondering how many the champions would score after Rooney drilled home in the 13th minute.
The England striker linked with up with Fabio and Young before shifting inside the area and firing low into Foster's bottom left corner.
United produced some controlled pinball in and around the penalty area. Nani, Rooney and Danny Welbeck knocked one-touch passes between themselves before Nani scooped over. Moments later, the Portugal international fired over again when former United keeper Foster failed to deal with a cross.
We deserved a point - Hodgson
The visitors' setup was upset after the break when centre-backs Nemanja Vidic and Rio Ferdinand were forced to come off with injuries. The average age of the starting XI was 23.9 years and that was lowered when Jonny Evans and Phil Jones came on as replacements.
It was lucky for the pair that only Long's movement and Somen Tchoyi's crossing raised their heartrates during the second half.
At the other end, United replaced Welbeck with experienced striker Dimitar Berbatov, hoping that a moment of Bulgarian magic would gift them victory.
But as it was, it was a moment of good fortune which gave the champions the perfect start.
West Brom manager Roy Hodgson:
"It was close. Our performance was very good, and we're sad not to hold on but very pleased with our team's performance.
"We played ourselves into the game and deserved a result for long periods of the game, but unfortunately Young got that bit of luck and that changed the complexion of things.
"We knew it was going to be tough, but we kept our end up well and consider ourselves a little bit unlucky not to get something from the game.
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