The 30-year-old England goalkeeper is well aware that the Baggies are facing a scrap to avoid relegation after Saturday's 2-0 defeat at Hull City left them in 16th spot, just three points clear of third-bottom Sunderland but having played two games more.
Albion face a massive six-pointer when second-bottom Cardiff City arrive at the Hawthorns on Saturday looking to try and pull level on points with Pepe Mel's men.
However, despite West Brom facing an injury and suspension crisis with up to five players - Jonas Olsson, Chris Brunt, Diego Lugano, Gareth McAuley, Victor Anichebe - set to miss out and Billy Jones and Morgan Amalfitano both doubtful, Foster is still looking to win the game.
If West Brom come out on top then the former Manchester United shot-stopper is confident that they would only require two more wins to be certain of top-flight football next term.
He said on the club's website: "I think you'll only need 36 or 37 points to be safe this season. Hull was a big game but we've got to put that behind us now and move on because Cardiff is massive - another six-pointer.
"Results went for us at the weekend so we're quite lucky in that sense but we can't focus on them too much, we need to start picking points up as well."