Kent Hrbek hit a grand slam and Gary Gaetti hit a three-run homer to power a 15-hit attack as Minnesota beat Seattle in Minneapolis.
John Butcher (9-11) yielded 10 hits over eight innings to record his first victory over the Mariners as a Twin. Matt Young (7-14) took the loss.
The Twins sent 12 players to the plate in an eight-run fourth to take a 9-0 lead.
Hrbek and Dave Engle singled and Tom Brunansky walked to load the bases with no outs. Hatcher followed with a single to center, driving in Hrbek and Brunansky to make it 3-0. Tim Teufel bunted toward third base but Seattle's Jim Presley overthrew first and the ball rolled into the Mariners' bullpen along right field, allowing Engle and Mickey Hatcher to score on the error.
Teufel, who had reached third on the play, then reached home on Ron Washington's single to center to make it 6-0 and chase Matt Young. Dave Meier greeted reliever Robert Young with a hard hit ball to left that stuck in a vent screen for a ground rule double, holding Washington at third. One out later, Gaetti hit his 13th home run of the season.