Gustav II Adolf vs. Johann Tserclaes (Tilly); the Battle of Breitenfeld (1631)
Gustav II Adolf vs. Albrecht von Wallenstein; the Battle of Lützen (1632)

Overall, the Thiry Years' War was littered with battles between excellent generals. I could probably dig up a few including the way too seldomly recognized Ottavio Piccolomini against some other general.