LONDON (AFP) Manchester United squandered a two-goal lead to draw 2-2 with West Bromwich Albion as Sir Alex Fergusons decision to leave Wayne Rooney on the bench backfired Saturday. United looked to be cruising to three precious Premier League points after goals from Mexican international Javier Hernandez and Nani fired the Red Devils into a 2-0 lead after 25 minutes at Old Trafford. But West Bromwich Albion pulled a goal back on 50 minutes when Patrice Evra deflected a Chris Brunt free-kick into his own goal, before an Edwin Van der Sar howler five minutes later gifted Somen Tchoyi an equaliser. It was the third time this season United failed to take all three points after leading and Ferguson admitted his team needed to rediscover their killer instinct after an unacceptable loss of two points. We created some really glorious chances in the first half to kill the game off, Ferguson told Sky Sports. Its frustrating because it turned a really top performance into one where weve dropped two points. Its not acceptable for anyone the supporters, myself, the players. We really need to dig a little bit deeper when we get chances to kill teams off. Ferguson meanwhile refused to point the finger at Van der Sar after the veteran Dutch keepers blunder. Youve just got to forgive him that, Ferguson said. I said to him probably the last time he made a mistake like that was at primary school. Its just inexplicable. Ferguson did not comment about the other major talking point of the day his decision to bench Rooney. The move came amid heightened speculation of tension between Ferguson and Rooney, who last week openly contradicted the United bosss claims he was injured by defiantly stating he was fully fit. In the late game, Chelsea missed the chance to stretch their lead over United to seven points after they could only draw 0-0 at Aston Villa.