Washington scored a 2-0 victory over Miami on Friday night, thanks to a few big hits and strong pitching.
Before Saturday's National League East battle with Washington, Guillen said the division's good pitching will probably force a lot of tight games.
"[I] expect close games most of the time," Guillen said. "We know that our division's pretty good."
But Guillen said his pitching staff, ranked sixth in the NL in ERA, has impressed with its early work. That's the kind of thing good teams need to have a shot at being competitive.
"I'm very excited about the way we play," Guillen said. "We're pitching well. That's very important."