SEATTLE — Taijuan Walker did his job, turning around two ugly starts to begin the season for Seattle and finally flashing the success he showed in spring training.
He failed to get rewarded because of another late meltdown by the Mariners' bullpen helped along by an uncommon error by Robinson Cano.
"We had a lot of good things going for us tonight and obviously it's tough to lose one like this," Seattle manager Lloyd McClendon said. "Anytime you lose games late that you know you've got a grasp around and think you should win it's tough."
Down 3-1 entering the eighth, the Astros scored five times against Mariners relievers, 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.
Seattle pitchers had done their jobs at keeping Altuve from getting going until Danny Farquhar left an 0-2 pitch over the middle of the plate.
"That was terribly located," Farquhar said. "I got away with the first two and was trying to go up and away and left it over the middle."
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.
"He was outstanding. He did exactly what I thought he was going to do," McClendon said. "Obviously the pitch count got up a little bit but he pounded the zone. He pitched off his fastball very well."
But Seattle couldn't finish off the victory for Walker and Cano was a big reason why. Cano mishandled 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 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.
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 and he allowed three earned runs. Chad Qualls pitched the ninth for his first save this season.
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."
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.
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.