Saint Louis let a first-half lead slip away and fell 67-63 at Massachusetts on Tuesday night.
The Billikens dip to 18-8 overall and 7-6 with the loss, while UMass improved to 11-15 and 5-8 in league play.
Jordan Goodwin led the Billikens with 22 points and 14 rebounds. It was his second straight double-double and 12th of the season. Goodwin also posted four assists and four steals.
Javonte Perkins registered 19 points, thanks in part to three treys. Demarius Jacobs chipped in 10 points for the Billikens.
SLU shot 50 percent or better from the floor for the second straight game, finishing 26-52 from the field. However, the Billikens did not make a 3-pointer in the second half after hitting five in the first half.
Tre Mitchell led UMass with 24 points, with 22 of those coming in the second half.
The Billikens used several 10-0 spurts in the first half and built a 16-point lead at 31-15 lead at the 7:17 mark of the first half.
But UMass slowly chipped away at the deficit and trailed by just seven at halftime, 35-28.
The Minutemen, who posted their 10th win at home, shot 57.7 percent in the second half. They took the lead for good on a 3-pointer by Carl Pierre at the 1:49 mark.
SLU is back in action on Friday night when it plays host to VCU at Chaifetz Arena. Game time on ESPN2 is slated for 8 p.m.
