SEATTLE -- The Houston Astros' long journey back to playoff possibility probably has to make a successful trip through Seattle if this team is going to return to the postseason. And there's no place starting pitcher Collin McHugh would rather be.

McHugh dominated the Seattle bats again Friday night, throwing seven shutout innings while beating the Mariners for the fourth time this season in the Astros' 6-0 win at Safeco Field.

"We just match up pretty well with them -- me, specifically," McHugh said after allowing just two hits while dropping his season ERA against Seattle to 1.36. "Whether it's pitch mix or this venue, I've been able to have some success against them."

McHugh (11-10) has now beaten Seattle nine times in 12 career decisions against the Mariners, and Friday's win might have been his biggest. It helped the Astros (77-70) remain four games behind co-wild-card leaders Baltimore and Toronto in the American League. Seattle fell to three games back.

"We needed that on a lot of levels," Astros manager A.J. Hinch said. "Every game is magnified this time of year, and we were playing against a team that we're chasing. ... Collin was fantastic tonight."

Home runs from Evan Gattis and Marwin Gonzalez helped the Astros chase Seattle starter Felix Hernandez in the fifth inning on the way to snapping the Mariners' eight-game winning streak on Friday night.

"Sometimes you get a clunker like that," Seattle manager Scott Servais said. "Not exactly what we were looking for tonight, but it does happen. ... We've still got a lot of ball left to play, we're still in a very competitive spot, but that's just not what we wanted to see."

Houston had nine hits -- eight in Hernandez's 4 1/3 innings -- while improving to 9-5 against the Mariners this season. Second baseman Jose Altuve had two hits and reached base in each of his first four plate appearances. Teammate Jake Marisnick went 2-for-4 with a two-run double. Gonzalez also went 2-for-4, scoring twice while hitting his 13th home run of the season.

"We got a big win tonight," Altuve said. "Collin threw the ball tremendous. A big win. We've got to come back (Saturday) and do the same thing."

Seattle left fielder Norichika Aoki, third baseman Kyle Seager and pinch-hitter Shawn O'Malley each had a single, accounting for the Mariners' only three hits. Shortstop Ketel Marte went 0-for-3 to see his five-game hitting streak end.

Gattis and Gonzalez each hit a fifth-inning solo homer as the Astros jumped out to a 6-0 lead while chasing Hernandez after 4 1/3 innings.

Gattis led off the fifth with his 27th home run of the season, then Gonzalez added his 13th homer two batters later.

Marisnick gave the Astros a 2-0 lead with a two-run double in the top of the second. Shortstop Carlos Correa added an RBI double in the third, putting Houston ahead 3-0.

Marisnick scored on a fourth-inning single by Yuli Gurriel, barely beating a nice throw from Aoki in left when he slid around the tag at home for a 4-0 Houston lead.

Gattis and Gonzalez both went deep in the fifth, sending Hernandez to the bench after 89 pitches. Hernandez allowed six runs (five earned) and eight hits in 4 1/3 innings.

"He certainly was not on top of his game tonight," Servais said.

The opposite could be said for McHugh, who didn't allow a hit until the fourth and was in control all night.

"He's pitched very well against us," Servais said. "We just don't see the ball well off him. We knew going into (Friday) it was going to be a challenge for us, but he certainly was on top of his game."

NOTES: Astros 2B Jose Altuve, who came out of Wednesday's game with a strained oblique, was in the lineup. He went into the Seattle series with a .336 career batting average against the Mariners. ... MLB.com reported that Astros INF Alex Bregman is expected to miss the rest of the season because of a strained hamstring. Bregman suffered the injury in Wednesday's win over Texas. ... Seattle 1B Dan Vogelbach got his third start of the season. Vogelbach, who was a key piece in the July trade that sent LHP Mike Montgomery to the Chicago Cubs, was promoted from Triple-A Tacoma on Sept. 12 and has been an important addition as veteran 1B Adam Lind, also a left-handed hitter, is battling a sprained finger. ... RHP Collin McHugh improved to 4-0 with a 1.36 ERA against Seattle this season, and he's 7-10 with a 5.30 ERA against everyone else. ... The Astros recalled INF Colin Moran from Triple-A before Friday's game.