SEATTLE -- Collin McHugh continued to linger, never getting knocked around enough to where his night needed to end, even if it felt as if there were constantly runners on base.

That grinding effort by Houston's young rising star pitcher was eventually rewarded by Jose Altuve, who hit a go-ahead three-run double in the eighth inning that gave the Astros a 6-3 win over the Seattle Mariners on Tuesday.

McHugh was far from his best. But Altuve's clutch hit -- coming on an 0-2 pitch -- helped McHugh win his 10th straight decision.

"It was a battle for seven innings and our guys picked me up every way they could," McHugh said.

Down 3-1 entering the eighth, the Astros scored five times against the Mariners bullpen, capped by Altuve's bases-clearing liner into the left-field corner for their fourth straight victory. Altuve had been hitless in his previous eight at-bats.

The rally made a surprise winner out of McHugh (3-0) and continued the longest winning streak by a Houston pitcher since Wade Miller won 12 straight decisions during the 2002 season. McHugh gave up three runs, but pitched through the seventh and stayed in the game long enough for the Astros to rally.

McHugh's seven innings were a season high, but he was far from sharp early. The three earned runs were also a season high and he struck out only three batters after striking out 11 in his last start against Oakland. The three strikeouts for McHugh were the fewest in his previous seven starts.

"I don't put a whole lot of an emphasis on the winning streak but tonight was big," McHugh said. "To be able to battle through some innings was tough."

Chad Qualls pitched the ninth for his first save this season.

McHugh's streak continued thanks to a rally that started because of an error committed by Seattle's Robinson Cano mishandling pinch-hitter Robbie Grossman's grounder leading off the eighth. Marwin Gonzalez followed with a base hit that eluded Cano and put runners at the corners. Slumping Chris Carter lined an RBI single off Charlie Furbush to score Grossman.

Furbush (0-1) was pulled for Danny Farquhar but the rally continued. Jed Lowrie walked on a full count and Jake Marisnick followed with a single on the first pitch to score Gonzalez and tie the game at 3-3. Altuve then delivered the big blow that cleared the bases.

"We needed only one run in that situation and fortunately I got the hit but I think the guys in front of me did it all," Altuve said.

Taijuan Walker was in line for his first victory of the season -- and the first by a Seattle starter other than Felix Hernandez -- before the failures of the bullpen. Walker matched his career high with eight strikeouts and pitched into the sixth, allowing just one earned run. Walker lowered his ERA by nearly 7 points after allowed 14 earned runs in his first two starts.

"We just imploded in the eighth," Seattle manager Lloyd McClendon said. "I thought we were in a real good position to win a ballgame and just couldn't close it out."

MISSED COUNT

Walker should have had one less strikeout and one more walk. George Springer struck out on a 3-2 pitch in the fifth, part of a perfect inning by Walker. But in a case of a mistaken count, the strikeout came after Walker had already thrown four balls.

"I think everybody in the ballpark pretty much missed it, which ultimately falls on me," Houston manager A.J. Hinch said. "I've got to be up out of the dugout again and make sure. There was a lot of confusion on that and fortunately for us it didn't burn us."

TRAINER'S ROOM

Astros: Reliever Josh Fields (groin) appears ready to return from his rehab assignment at Triple-A Fresno. Fields made his fifth appearance with Fresno on Monday, but the Astros are not ready to announce plans for his return.

Mariners: Reliever Tom Wilhelmsen (hyperextended elbow) is expected to start a throwing program later this week. Manager Lloyd McClendon said Wilhelmsen will likely need a few rehab innings before rejoining Seattle's bullpen.

UP NEXT

Astros: Roberto Hernandez (0-1) looks for his first win with Houston. Hernandez hasn't pitched at Safeco Field since August 2012.

Mariners: J.A. Happ (0-1) looks to build on two strong outings thus far. Happ has allowed only two earned runs in each of his first two starts but is yet to get a victory.