HOUSTON — Lance McCullers wasn't upset that he didn't get a chance to return for the sixth after throwing five hitless innings Sunday.
The rookie was just glad he did enough to help Houston get a win.
McCullers and four relievers combined for a two-hitter, Evan Gattis tied a career high with four hits and the Astros cruised to a 13-0 victory over the Seattle Mariners.
"We pitch to win ball games and to get this team down the road into the playoffs and to pitch in the playoffs," McCullers said. "Not going back out there was not a big deal."
The win gives Houston five straight series wins against Seattle, which marks the first time they've won five in a row over one opponent since 2010 when they did it against the Cubs.
McCullers (3-1) struck out four through five, but he needed 90 pitches to get through those innings because of four walks.
Manager A.J. Hinch said McCullers couldn't have talked him into staying in the game.
"It's not really a negotiation so I told Lance, 'You're done,' and he said, 'OK,'" Hinch said. "These guys all want to pitch as long as they can. It's always one extra inning or one extra out or one extra batter and that's what you want from your guys, but he was done when he was done."
He was replaced by Tony Sipp for the sixth inning and Austin Jackson doubled with one out in the inning.
Joe Thatcher allowed one hit in the seventh, Will Harris threw a perfect eighth and Josh Fields completed the shutout.
Colby Rasmus had three RBIs as the Astros built a 10-0 lead by the fourth inning on a day where all but one player in the starting lineup had a hit.
Seattle starter Roenis Elias (3-4) was roughed up for seven hits and a career-high eight runs in 3 1-3 innings in his shortest start of the season.
"He just didn't have much command today, and it was a tough day for him in a lot of different ways," manager Lloyd McClendon said.
The 21-year-old McCullers has been great for Houston since making the jump from Double-A. He has a 2.00 ERA in six starts.
"All these are growing experiences for Lance," Hinch said. "He's learning that he's going to have to win in different ways. He doesn't have to be dominant every time, he doesn't have to do it all himself."
The Astros were playing without All-Star second baseman Jose Altuve, who missed his second straight game with a strained right hamstring. Marwin Gonzalez filled in and had a homer and two RBIs.
The Mariners won 8-1 on Saturday, but their offensive woes returned on Sunday as they struck out 10 times and were shut out for the second time in this series and third time in four games.
Rasmus drove in two runs with a single in the first inning and the Astros made it 3-0 when Jake Marisnick reached and Chris Carter scored on an error by Kyle Seager.
A ground-rule RBI double by Marisnick and a bases-loaded walk in the third pushed it to 5-0. A run-scoring single by Rasmus made it 6-0 with one out in the fourth and chased Elias.
He was replaced by Danny Farquhar, but it didn't do anything to slow Houston down. He was greeted with a double by Hank Conger that sent two more home before a two-run homer by Luis Valbuena extended the lead to double digits with two outs in the inning.
He finally escaped the inning when Gonzalez grounded out.
Mark Lowe walked Conger with the bases loaded in the fifth inning to extend the lead to 11-0 and end a streak of 15 1-3 scoreless innings for the reliever.
Gonzalez hit a solo homer off Charlie Furbush in the sixth and Preston Tucker added an RBI double in the eighth.
Seattle's Logan Morrison had hit in every game in his career at Minute Maid Park, but went 0 for 4 on Sunday to snap the 18-game streak in Houston.
Mariners: Left fielder Mark Trumbo was a late scratch with back spasms. He said he doesn't think it is serious but isn't sure if he'll play on Monday.
Astros: Hinch said that Altuve was feeling better on Sunday and that they don't think his injury is serious. He is day to day.
Mariners: Right-hander Taijuan Walker opposes San Francisco's Tim Hudson when the Mariners begin a two-game interleague series against the Giants on Monday. Walker is 2-1 with a 1.64 ERA in his last three starts.
Astros: Left-hander Dallas Keuchel faces Colorado's Chad Bettis in the first game of a two-game series with the Rockies on Monday. Keuchel is second in the AL with a 1.90 ERA.