McHugh and Fiers became the first Astros pitchers to have consecutive scoreless outings of at least six innings since Scott Feldman and Dallas Keuchel on Aug. 24-25, 2015, against the Yankees in New York.
"We needed all the good pitching we could get, based on how their guy [James Paxton] was throwing," Astros manager A.J. Hinch said. "It was another good outing by our starters, and if we can get that, we're a pretty interesting team. We usually find a way. I like the tone our starters have set the last couple of days."
Fiers retired 17 of the final 19 batters he faced after allowing a pair of singles to start the game, and he didn't allow a runner to reach third base all night. He walked only one batter and struck out four while allowing two singles and a double.
"His fastball was good, his curveball was a strike, his changeup was pretty good," Hinch said. "He threw some 3-2 changeups when he got into a little bit of some jeopardy with some long at-bats he used his weapons and used them well. He's a pitch-mix guy and has a little sneaky fastball when he throws strikes and a pretty good curveball he can land when he's timed up. He had a little bit of everything working."
Fiers (11-7) retired Mariners second baseman Robinson Cano three times, twice with men on base. The slugger came into the game 2-for-3 in his career against Fiers, with both hits home runs.
"I threw first-pitch strikes and tried to stay in good counts and stay away from their counts, the 2-0's, 3-1's, and just attack them early with my stuff and believe in my stuff and trust the defense behind me," Fiers said. "I was able to do that."
Fiers will next hand the baton to veteran Doug Fister, who's struggled mightily in last four starts but is 2-1 with a 4.67 ERA in three career starts against the Mariners. The Astros need another good start if they want to keep pace in a crowded American League Wild Card race. Houston enters Sunday's series finale tied with Seattle and Detroit, three games behind Wild Card leaders Toronto and Baltimore.
"We've got a great starting rotation and maybe things haven't gone the way people want it to be, but we're still going out there and trying to do our job and not worry about everybody else," Fiers said. "Just go game to game and I've got to do my job and tomorrow's Doug's got to do his job and on from that. Just take it from ourselves to put up a quality start and keep us in the game and give our hitters a chance to win with that."
Brian McTaggart has covered the Astros since 2004, and for MLB.com since 2009. Follow @brianmctaggart on Twitter and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.