Man Utd boss Ferguson plays down Foster howler
The second was a personal disaster for Foster, who mis-controlled Darron Gibson's back pass after replacing Edwin van der Sar at the break to provide Yahyah with a tap-in.
For a player looking to put some pressure on Van der Sar this term in order to prove worthy of being United's new number one when the veteran Dutchman hangs up his gloves in the summer, it was not the ideal start to the season.
However, Ferguson did not appear too distressed and insisted he has plenty of faith in the former Stoke man.
"Ben has had ligament damage in his finger and that was his first game for a few months," said the United boss.
"It was a big day for him coming back after such a long time and I am not too concerned.
"I have said I think he will be England's number one keeper and I still believe that."