HOUSTON -- The Seattle Mariners used a power display to help out their young starter -- and improve their playoff chances.
Ackley homered in the third and eighth innings for his second career multihomer game for the Mariners, who moved a 1/2 game back for the second AL wild card with the victory and Royals' loss to Detroit.
"I felt good today," said Ackley, who has a career-high 13 homers this season. "I don't know what it was, going into the game. Sometimes you come to a park and it's just one of those places where you get a good feeling about it and that's pretty much the way it was."
Twenty-one-year-old rookie Taijuan Walker (2-2) yielded eight hits and two runs with seven strikeouts in 5 2/3 innings for his third career win in his return to the rotation for injured left-hander Roenis Elias. It was his first start since July 23.
"I think eight runs helped him quite a bit," manager Lloyd McClendon said. "But he knows that club. He knows what they're capable of doing. More than anything he executed pitches very well tonight. I can't tell you how pleased I was with his execution and his command of the strike zone."
Four of Walker's seven career starts have come against the Astros and each of his wins have been in Houston.
"It's kind of like my home park, I guess," he said with a laugh. "Home-field advantage."
The game was tied at 1 before things fell apart for the Astros in the fourth inning. Logan Morrison reached on an error by Jonathan Villar and an error by Chris Carter allowed Michael Saunders to reach with no outs.
Zunino's homer, which bounced off the wall in left-center, came next to make it 4-1. Brad Peacock (4-9) walked two batters with one out before Robinson Cano chased him with a single for his 900th career RBI.
"Those were two routine groundballs, and they turned into a three-run homer," interim manager Tom Lawless said of the errors. "You make those plays, and there's nobody on and two outs. That's the importance of playing defense."
Peacock was replaced by Jake Buchanan, who was greeted with Seager's three-run homer which landed in the bullpen in right-center and pushed the lead to 8-1.
Major league hits leader Jose Altuve bounced back from Thursday's 0 for 6 night with three hits to give him 216, which are the most by a second basemen since Rod Carew had 218 in 1974. It's his 24th three-hit game this season, which sets a franchise record, and he tied Magglio Ordonez for most hits by a Venezuelan player in major league history.
"I was 0 for 6 last night and I knew I wasn't going to go 0 for 6 again," Altuve said. "I tried to go up there, swing the bat. I saw like three pitches, three or four. I was ready to swing."
Peacock allowed six hits and seven runs -- two earned -- with four walks in 3 1/3 innings in a game where seven of Seattle's 10 runs were unearned.
Ackley tied it at 1 with a home run in the third inning. His second homer was off Darin Downs and pushed the lead to 9-3 in the eighth.
Mariners: Elias had an MRI in Seattle on Friday after feeling stiffness in his elbow. Manager Lloyd McClendon said that they won't know the results of the MRI until Monday.
Astros: Downs left Friday night's game after the homer to Ackley with discomfort in his right oblique.
Houston's Dallas Keuchel opposes Chris Young when the series continues on Saturday. Keuchel is first in the American League with five complete games. Young has tied his career-high in wins with 12 this season and is 1-0 with a 3.21 ERA in two starts against Houston this season.