"I turned the match in the second set and even when I was 3-1 down in the third I felt in control," Stepanek said.
"It's going to be a tough final, but I am prepared for it," Stepanek added.
Both Stepanek, the tournament's sixth-seed, and Rochus will be after their first ATP singles title. The winner pockets $175,000.
The 27-year-old Stepanek has lost three previous finals. Rochus lost his only final appearance at Valencia in 2003.