SEATTLE (AP) -- Collin McHugh didn't know he was starting Tuesday until late the night before. When he took the mound, he surprised just about everyone with his performance.
McHugh (1-0) was told he was being called up from Triple-A Oklahoma City on Monday and flew to Seattle. It wasn't until he got to the team hotel late Monday night that he found out he was going to start for the Astros on Tuesday.
Before the game, Houston coach Bo Porter characterized McHugh as a ''pitch to contact guy,'' but the Mariners made almost no contact. McHugh struck out the first three batters he faced to set the tone for his first win in 10 career starts.
''That was outstanding. That's what you call seizing the opportunity,'' Porter said.
The right-hander didn't walk a batter, giving up three hits in 6 2-3 shutout innings.
''I don't think anybody prepares to go out and strike out a bunch of people. But I knew I had pretty decent command today with two or three pitches,'' McHugh said. ''It was really good to kind of get the proverbial gorilla off your back with a W.''
McHugh's stuff caught the Mariners off guard as well, as they only reached second once against him.
''He was a little different than the scouting report we got. He was 94 (miles an hour) with a pretty good cut slider,'' Seattle manager Lloyd McClendon said. ''He threw exceptionally well tonight.''
Seattle starter Erasmo Ramirez (1-3) struck out eight over six innings and only allowed three hits, but they included the two costly homers.
Three at-bats into the game, Castro just cleared the left field wall for a two-run homer, his fourth. Carter followed in the second inning with a shot to left that landed in the second deck for his first homer of the year.
Seattle's Dustin Ackley tried to counter with a deep ball to left in the bottom of the second, but Matt Dominguez made a leaping catch at the wall to end the inning.
Dominguez added a homer of his own in the top of the seventh to give Houston a 4-0 lead.
The Astros have now won two in a row after a seven-game losing streak, and their offense - which entered Tuesday's game with a major league-worst .196 batting average - is finally showing some signs of life.
''Once the whole offense is flowing like it is the last couple games, you kind of get in a little groove with it,'' Dominguez said. ''It's been nice being able to score some runs.''
McHugh's 12th strikeout came against Robinson Cano to leadoff the bottom of the seventh, but Porter brought on reliever Raul Valdes with two outs in the inning. McHugh had thrown 89 pitches, well above his high of 73 pitches in his minor league outings this year.
Valdes walked Kyle Seager and then gave up a two-run home run to Justin Smoak, Seattle's only offense of the game.
McHugh's call up came after Scott Feldman was placed on the disabled list with biceps tendinitis. Feldman will miss at least one more start, possibly giving McHugh more chances to show what he can do.
''He didn't do anything to hurt his chances of sticking around,'' Porter said. ''He definitely earned his keep.''
NOTES: The crowd of 10,466 was the fifth-lowest in Safeco Field history. Six of the seven lowest crowds at Safeco have been matchups with the Astros, all coming since the start of last season. ... Seattle RHP Hisashi Iwakuma (finger) was scheduled to pitch in a rehabilitation assignment at Triple-A Tacoma, but instead threw a simulated game at Safeco Field on Tuesday afternoon due to weather concerns. McClendon said the outing went well, and Iwakuma will have a rehab outing with Tacoma on Sunday. ... Astros RHP Lucas Harrell, designated for assignment on April 16, cleared waivers and was outrighted to Triple-A Oklahoma City.