Alberto Callaspo hit a three-run homer and Mitch Maier added a solo shot in a four-run eighth inning and the Kansas City Royals rallied for a 7-3 victory over the Seattle Mariners on Wednesday night.

Billy Butler had two hits, including a home run, and a pair of RBIs as Kansas City swept the three-game set, the club's first sweep in Seattle since 1995.

Nursing a one-run lead in the eighth, Mariners reliever Brandon League (5-6) walked David DeJesus and Butler. Callaspo, who had not homered since May 20, drilled a shot to deep right. Mitch Maier made it 6-3 in favor of the Royals with homer to right off Garrett Olson.

Victor Marte (3-0) earned the win with one inning of relief and Joakim Soria got his major-league best 25th save as Kansas City has now won 10 of 13.

Casey Kotchman hit two home runs – a two-run shot in the sixth and solo shot in the second – for Seattle off starter Kyle Davies, who allowed three runs on four hits in six innings.

Mariners starter Doug Fister allowed one run on six hits in six innings in the no-decision.

Butler hit his ninth homer in the ninth, a ball originally ruled a double but reversed after a video review, after giving the Royals a 1-0 lead in the first with a sacrifice fly.