SEATTLE -- Houston third baseman Luis Valbuena hit two solo home runs, including the go-ahead shot in the eighth inning, and the American West-leading Astros earned a 7-5 win over the Seattle Mariners on Monday night.

Valbuena gave Houston a 1-0 lead in the first inning with a blast to center, and he led off the eighth with his third in two days to put the Astros ahead 6-5. Shortstop Jed Lowrie added his second RBI for an insurance run.

Houston closer Luke Gregerson pitched a scoreless ninth inning to record his third save of the season.

Astros reliever Tony Sipp (1-0) got the win on a night when neither starter was very effective. Seattle reliever Danny Farquhar (0-1) gave up two runs in the eighth to absorb the loss.

The Mariners had 10 hits, with second baseman Robinson Cano, right fielder Nelson Cruz and third baseman Kyle Seager combining for six of them, but it wasn't enough.

Seattle starter Hisashi Iwakuma allowed four earned runs on five hits over 5 1/3 innings. He gave up two home runs.

Lowrie went 2-for-4 with two RBI singles for the Astros, who won their third game in a row. Second baseman Jose Altuve went 0-for-4 to snap his nine-game hitting streak.

The heart of Seattle's order continued to wreak havoc, accounting for four of Seattle's five runs on the way to a 5-3 lead through the fifth. No. 3 hitter Cano scored twice, cleanup hitter Cruz drove in a pair of runs and No. 5 batter Seager scored one run and drove in another.

The Mariners overcame solo home runs from Houston left fielder Colby Rasmus and Valbuena.

After Valbuena's first homer, Seattle (5-8) tied the score 1-1 on an RBI single from shortstop Brad Miller in the second inning before the Astros regained the lead by manufacturing a run in the top of the third. Center fielder Jake Marisnick led off the inning with a double, moved to second on a sacrifice bunt and scored on Valbuena's sacrifice fly to give Houston (7-6) a 2-1 lead.

Astros starter Asher Wojciechowski pitched himself into and out of trouble in the third by allowing back-to-back-to-back hits, but the Mariners managed only one run. Cruz's RBI single tied the score 2-2 before Seattle loaded the bases -- only to leave three runners stranded when catcher Mike Zunino struck out and first baseman Logan Morrison popped out to center field.

Rasmus hit a one-out solo shot in the top of the fifth as Houston took a 3-2 lead, then Cruz struck again with an RBI double in the fifth, tying the score at 3.

Seager followed that with a single to center that gave the Mariners their first lead, 4-3. Seager came in to score on Zunino's sacrifice fly as Seattle went ahead 5-3 in the fifth.

Wojciechowski was lifted after Cruz's fifth-inning double. He was charged with four runs on eight hits in four-plus innings.

NOTES: Mariners RF Nelson Cruz was named the American League Player of the Week before Monday's game. Cruz hit .500 (12 for 24) with six home runs and 10 RBIs during the six games played last week. ... Houston's Collin McHugh, who is scheduled to start Tuesday game in Seattle, has gone 9-0 with a 2.00 ERA since the beginning of August 2014. ... The Mariners' scheduled Tuesday starter, RHP Taijuan Walker, is 3-0 in four starts against the Astros during his career. He is 0-5 in all other games. ... The Astros played their first game of the season outside of the state of Texas on Monday. Houston had nine home games and a three-game road series against the Rangers heading into the Seattle trip.