HOUSTON (Interstat) — J.P. Crawford hit a grand slam and Cal Raleigh slugged his major league-leading 58th home run in a seven-run second inning, powering the Seattle Mariners to a 7-3 victory over the Houston Astros on Sunday night at Daikin Park.

The Mariners completed a three-game sweep that gave them a commanding three-game lead in the AL West over the Astros with just six games remaining in the regular season. Seattle, which has won four straight and 14 of its last 15, improved to 87-69. Houston fell to 84-72.

Seattle, looking to win the AL West for the first time since 2001, finished the season series with an 8-5 record against its division rival. The Mariners also hold the second American League playoff seed by two games over AL Central-leading Detroit.

The game was decided in a chaotic top of the second inning against Astros starter Jason Alexander (4-2). Josh Naylor, Jorge Polanco and Eugenio Suárez opened the frame with three consecutive singles to load the bases. After a forceout at home, Victor Robles drew a walk to force in the game’s first run.

Crawford then cleared the bases, launching a grand slam, his 12th home run of the season, to right field to give Seattle a 5-0 lead. Randy Arozarena followed with a single, and Raleigh then punctuated the offensive explosion with a two-run homer, a line drive to right field that extended the lead to 7-0 and chased Alexander from the game.

That was more than enough support for Seattle starter Logan Gilbert (6-6), who earned the win with a strong outing. Gilbert pitched six innings, allowing just three hits and one earned run while striking out four. The lone run off him came on a solo home run by Houston’s Zach Cole in the bottom of the third inning.

The Astros bullpen, led by AJ Blubaugh’s three hitless innings of relief, kept Seattle’s offense quiet after the second, but the early deficit was too large to overcome. Houston added a run in the seventh on an RBI single by Jose Altuve and another in the eighth on a solo home run by Isaac Paredes, his 20th of the season.

Carlos Vargas and Matt Brash finished the game out of the Mariners’ bullpen to secure the series sweep.

The announced attendance was 41,893, and the game took 2 hours, 50 minutes to complete. The combined score of 10 runs went under the pregame over/under line of 8. The Mariners collected eight hits to the Astros’ seven.

Seattle returns home to begin a three-game series against the Colorado Rockies on Tuesday. Houston heads west to open a three-game set against the Athletics on Tuesday.