Birmingham boss Alex McLeish has hailed his goalkeeper Ben Foster as "world class" despite his costly blunder in the Carling Cup loss at West Ham.McLeish said: "On coaching courses, I was taught international players have one off game in 15, world-class players have one off game in 25 or even more. [LNB]"Ben's statistics are of the world-class kind." [LNB]Foster will get a chance to atone for his mistake in Sunday's derby with Aston Villa at St Andrew's. [LNB]The 27-year-old has been in fine form since his £6m summer move from Manchester United and has regained his spot in the England squad. [LNB]But his error at Upton Park, when he allowed a soft shot from Carlton Cole to slip underneath his legs, gifted the Hammers a 2-1 semi-final first-leg win. [LNB]McLeish said: "Keepers are in that unfortunate world where a mistake normally leads to a goal.[LNB] Foster is still my player of the season - he kept us in it in the first half at West Ham and in a lot of games this season bluenose-1875 "Ben made mistakes at Manchester United and recovered from them. He is a fantastic keeper. [LNB]"The big man has saved us many points this season and been excellent in every game. He is human and will bounce back, and I'm sure he will want to atone." [LNB]Villa head to St Andrew's in the bottom three of the Premier League but McLeish expects them to pull clear of danger by the end of the season. [LNB]He said: "Is it a surprise to see Villa in the bottom three? The Premier League is unforgiving. It is not to be taken for granted. I would never do that and I don't think [Villa boss] Gerard Houllier would either. [LNB]"People say it is a surprise but it can happen to any team. Middlesbrough spent millions a few years ago and got relegated. It doesn't guarantee anything, spending money. [LNB]"It is about team building and getting the very best out of your players. Villa have got a lot of good players and I'm sure they won't be there [in the bottom three] at the end of the season."