Marwin Gonzalez capped a four-run third inning with a two-run home run, and rookie Josh James earned his first major league win during the Houston Astros' 7-0 win over the visiting Seattle Mariners on Tuesday.

With the victory, their 13th in 16 games this month, the Astros reduced their magic number to clinch a postseason berth to two. They also eliminated the Mariners from contention in the American League West.

The Astros' ambush of Seattle right-hander Mike Leake (10-10) was sudden. Leake had faced one batter over the minimum entering the third, but he opened that inning by plunking Brian McCann with a pitch.

Tony Kemp advanced McCann to third base with a double that eluded Mariners first baseman Robinson Cano before working its way into the right field corner. Springer followed with an RBI single to left that Denard Span misplayed into an extra base for Springer.

Jose Altuve's groundout scored Kemp before Gonzalez cranked his 16th home run out to left-center field, a 385-foot shot that extended the Houston lead to 4-0.

Leake then retired the side in order in the fourth, fifth and sixth innings before hitting trouble again in the seventh. Yuli Gurriel hit a one-out double and scored on a McCann single.

The Astros, who snapped a five-game home losing streak to the Mariners, can secure the season series from Seattle with a victory in the three-game series finale on Wednesday. Houston won the season series against its four AL West rivals last season and has already clinched the season series against its three other division foes excluding the Mariners this season.

James (1-0) was making a spot start for fellow right-hander Gerrit Cole, who had his start pushed back to Friday against the Los Angeles Angels. Per usual, James relied heavily on his fastball, unleashing 49 among his 87 pitches. He averaged 97 mph with the four-seamer in his fourth major league appearance and second start.

James faced three batters with runners in scoring position and responded with a strikeout of the ensuing batter each time. He allowed four hits and two walks with seven strikeouts over 5 1/3 innings.

Four Houston relievers assisted in closing out a six-hit shutout.

Leake gave up five runs on six hits in 6 1/3 innings.

--Field Level Media