DeForest won its second consecutive road playoff game on a buzzer beater on Saturday.
With the game tied at 42 with 5.5 seconds to play, DeForest had a baseline out-of-bounds play and senior Bryn Smith found sophomore Grace Roth for the game-winner.
There were 4.5 seconds left after Roth scored, but Monona Grove, with Iowa recruit McKenna Warnock on the bench after following out, was only able to get a half court heave up that fell well short of the basket.
DeForest got a team-high 9 points from junior Taylor Tschumper. Junior Sam Shaeffer, who scored the game winner against Oregon, netted 8 points and Roth added 7 for the Norkies.
Iowa recruit McKenna Warnock finished with a game-high 19 points and finished her storied career with 2,311 points.