The four-game winning streak the Twins (23-29) were riding came to a halt as they were blanked at home by the Mariners, 3-0 Friday night.
Hisashi Iwakuma scattered seven hits over 7 2/3 shutout innings. He put runners at first and second base with two outs in the eighth, but left-hander Charlie Furbush struck out Justin Morneau to end the threat.
Mike Pelfrey threw a lot of pitches, but was throwing a shutout until he gave up three runs in the sixth inning.
The damage was done by Kendrys Morales, who took Pelfrey deep to center for a two-run homer. Pelfrey then allowed the third run on a single to center by Jesus Sucre.
Only Chris Parmelee and Pedro Florimon found success against Iwakuwa. They combined for five of Minnesota's seven hits.
Tom Wilhelmsen pitched a 1-2-3 ninth for the save.
Saturday's game starts at 12:10 p.m. Kevin Correia starts for the Twins against Aaron Harang.