Van der Sar still retains backing of Man Utd boss
The Manchester United keeper was guilty of a howler in last weekend's Premier League fixture as the Red Devils surrendered a two-goal lead for the third time this season to allow the Baggies to claim a point at Old Trafford.
But Ferguson has backed the veteran shot-stopper to respond positively to his mistake in their midweek UEFA Champions League clash.
"The mistake was uncanny," said the United boss.
"Here is a player with 130 caps for Holland and the most fantastic career you could imagine and he makes a mistake like that.
"You cannot even criticise him because he doesn't deserve that.
"He is allowed to make one horrendous mistake in his life. It was at a time when we didn't need it, of course, but it happens.
"You just have to wash it away."