After beginning Midwest Conference play with a pair of victories on Saturday, the Foresters were defeated 9-0 by visiting Grinnell College on Sunday.
Grinnell entered the week ranked 10th in the region and 39th in the nation.
The closest match in doubles with at #2, where Forester sophomore Aidan Burke and junior Chase Garber were defeated 8-3. Burke's 6-3, 6-1 loss in singles was the best a Forester was able to do in that portion of the contest.
Lake Forest fell to 7-9 overall and 2-1 in the league while the Pioneers improved to 15-4 overall with victories in both of their conference matches.
The Foresters will continue league play at Illinois College and Monmouth College next Saturday.