"I've been in this situation before when you're playing good football but not getting results and you have to make sure that you don't slip into a rut," the Australian goalkeeper has told the club's official website.
"You've almost got to revert back to a bit of unattractive football and just make sure that you grind out results to lay that platform, get a run going and build on that.
"You know Portsmouth are going to be dangerous with Peter Crouch and Jermain Defoe up front."
Portsmouth play in a UEFA Cup tie on Thgursday night and Schwarzer is hoping that Fulham can take advantage of any possible tiredness amongst Harry Redknapp's ranks in the game at Fratton Park on Sunday evening.
"Hopefully they'll have a touch of UEFA Cup blues and we'll be able to take advantage of that," he added.