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. 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. The likes of young guns Tom Cleverley and Danny Welbeck have been loaned out in order to gain experience before they were handed their first-team opportunity, but Ferguson had no hesitation in giving £18m summer signing his league debut. 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. But 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 many must have been thinking how many the champions could score after Rooney drilled in on 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. United produced some controlled pinball in and around the penalty area. Nani, Rooney and Danny Welbeck knocked one-touch passes between each other before Nani scooped over. Moments later, the Portugal international fired over again when former United keeper Foster failed to deal with a cross. United's set-up was upset after the break when both centre-backs Nemanja Vidic and then Rio Ferdinand were forced to come off with injuries. The average age of the starting XI was 23.9 years and that was further lowered when Jonny Evans and Phil Jones came on the pitch. 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 the 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.