Myra Peterson shot a 41, Surya Vijayasankar added a 42, and Stevenson's girls golf team edged Vernon Hills at Vernon Hills Golf Course on Thursday.
Stevenson's 177 was three strokes better than Vernon Hills' total.
Vernon Hills' Faith Jung was the medalist with a 40.
Libertyville d. Deerfield: At Deerfield Golf Club, Maggie Piazzi earned medalist honors for the second day in a row, as her 40 led the Wildcats (165), whose 10-stroke win hiked their record to 7-0.
Libertyville, which won for the third time in as many days, also counted Jessica Lovinger's 41 and 42s from Simone Mikaelian and Megan Sturonas.
"All six played well," said Wildcats coach Greg Petersen, also noting the play of Reilly Burnetti (44) and Sara Keefe (46). "They were focused on finishing."
Mundelein d. Highland Park: At Countryside, the Mustangs (189) got a win over the Giants (202).
Mundelein's Megan Wiese and Jennifer Dimitriou shared medalist honors with 45s.
Johnsburg d. Grant: Kylie Diana shot a 49 for the Bulldogs in their 195-223 loss.