Schwarzer also contributed by saving Jonathan Walters' spotkick.
On Berbatov's goal, Schwarzer said: "We see it every day in training.
"We know what quality he has and expect it from him, which puts more pressure on him."
On the penalty save, the Australian veteran said: "We looked at video footage before the game so I was confident I knew where he was going to go. I was lucky enough to get behind it."
Schwarzer also made a good save to deny Peter Crouch and added on Sky Sports: "Any time you don't concede a goal is important.
"We needed the points today. You know what you are going to get from Stoke and it is especially vital at home to pick up three points."