The Cottagers stunned Liverpool 3-1 on Saturday.
And keeper Schwarzer told fulhamfc.com: "There's no secret to it - it's all about hard work. The Manager is adamant about the way he wants us to play and we are drilled day-in, day-out, in training.
"Everybody knows what they need to do and fights for each other. We've got some quality players. There are no superstars in the team but we're very difficult to break down and play against.
"It shows in the last 18 months - when I've spoken to fellow pros the first thing a lot of them have said is that Fulham are so well organised and difficult to beat.
"It was a good result on Saturday but the last 18 months have been pretty special overall I think and I hope over the next six months or so there will be more special days at the Cottage."