MIAMI (AP) -- The Houston Astros are playing so well they needed unbeaten ace Dallas Keuchel for only five innings Tuesday night.
The left-hander became the first seven-game winner in the majors despite his shortest outing this season, and Houston beat the sinking Miami Marlins 12-2.
Keuchel (7-0) threw only 70 pitches before departing with a 10-2 lead achieved in part thanks to a pair of two-run homers by Jake Marisnick .
"I don't like to pitch five innings," Keuchel said, "but if there's a big lead and I've got a chance to get a win, I'll take that. I'm on pace for a lot of innings, so today was a good chance to save a few bullets."
Keuchel is known to argue when he's taken out of games, but this time he offered little protest, manager A.J. Hinch said.
"He always wants to pitch, but he understands," Hinch said. "He's on board with what we're doing, and we have the big picture in mind when we do stuff like this."
The big picture is rosy for the Astros (28-12), who own the best record in the majors and have won six series in a row.
The last-place Marlins (14-24) are headed the other way, losing 16 of 20. They're 1-7 on their homestand going into Wednesday's finale.
"You're tired of these kind of games," manager Don Mattingly said.
Tom Koehler (1-2) gave up eight runs in three innings and was optioned to Triple-A New Orleans after the game. He won 30 games from 2014-16 but has an ERA of 7.04 this year.
"I've thrown a lot of innings in the big leagues and I've had success," Koehler said. "But this wasn't getting it done. … I'm just going to make sure everything's right, work on my delivery, and get back to what was making me successful in the past. And try to make this stint as short as possible."
Marisnick led the Astros' 14-hit attack and tripled his season RBI total to six. Both of his homers caromed off the home run sculpture at Marlins Park.
"I wasn't aiming for it," he said.
Marisnick also hit his first double of the year and acknowledged some satisfaction in having a good game against the team that traded him in 2014.
"It was a pretty cool feeling," he said.
Brian McCann also had four RBIs .
Keuchel allowed two runs, increasing his ERA to 1.84. Two infield hits, a wild pitch and two errors -- one by Keuchel -- helped the Marlins score twice in the first.
Keuchel's description of the inning?
"As colorful as Miami," he said. "Luckily, I settled down and made some good pitches."
Miami went hitless for the final 6 2/3 innings against Keuchel and two relievers, and totaled just four hits.
The Astros used five singles to score three times in the first inning. Koehler issued three consecutive two-out walks in the second, and McCann hit the next pitch for a three-run double.
The Astros' run total was a season high. They rank second in the AL in runs.
"Pretty impressive," Hinch said. "We kept coming at them and coming at them. We hit and hit and hit."
Keuchel made a throwing error in the first but also helped himself with the glove . He leads the majors in groundball outs, and the three-time Gold Glove winner had a fielding role in seven of the 15 outs he recorded. He had six assists, all on plays scored 1-3, and added a putout scored 4-1.
The Marlins claimed INF Christian Colon off waivers from the Royals and designated INF Steve Lombardozzi for assignment. Colon is a .263 hitter in 125 games over the past four years.
Astros: 2B Jose Altuve had a hit, two walks and scored twice one night after being hit by a pitch on the left hand.
Marlins: RHP Dan Straily (bruised right arm) said he's optimistic he'll make his next start as scheduled. He was hit by a line drive Monday and left the game after five innings. … LHP Wei-Yin Chen (tired arm) underwent an MRI and the team was awaiting results. He's expected to be shut down for at least two weeks.
The Astros will try for their first three-game sweep of the season Wednesday afternoon when RHP Lance McCullers Jr. (3-1, 2.98 ERA) starts against RHP Jose Urena (1-1, 1.98).