Montgomery, acquired from the Rays in the Erasmo Ramirez trade just before the season opener, threw six innings of one-run ball and is now 1-1 with a 1.89 ERA in three starts since being called up from Triple-A Tacoma.
The former Royals first-round Draft pick has now pitched six or more innings and allowed two runs or fewer against the Yankees, Rays and now Astros. He joins Bob Stoddard (1981) as the only Mariners pitchers to accomplish that feat in his first three career starts.
"It's been fun," Montgomery, who turns 26 on July 1, said of his sudden arrival in the Majors after eight years in the Royals and Rays organizations. "I always believed in myself and I'm really grateful for Seattle to kind of believe in me and give me the opportunity to make the most of it.
"I believe in what I do and now it's just a matter of going out there and proving it every fifth game and trusting this team. It's fun being part of a team this good and I think as the season goes on, we're going to show that."
Staked to a 5-0 lead, Montgomery avoided problems in the second when a two-out, two-on drive by Marwin Gonzalez died in Seth Smith's glove up against the short left-field wall at Minute Maid Park.
Seattle increased its lead to 8-0 before Houston finally nicked Montgomery in the fifth with back-to-back doubles by Jason Castro and George Springer. And when Montgomery followed by walking Carlos Correa, manager Lloyd McClendon quickly had just-recalled Danny Farquhar warming in the bullpen.
But Montgomery dug in and struck out Evan Gattis, then ended the threat with a groundout by Chris Carter to preserve the 8-1 advantage. He then zipped through the sixth before McClendon went to his bullpen with Montgomery having thrown 98 pitches.
"I thought he threw pretty decent early on," McClendon said. "But I don't think he really commanded the strike zone later in his outing as well as he did the two previous times. But all in all, it was a good outing for him. I think it was a credit to his catcher to get him through it. If we're really being honest, he struggled a little bit today."
Mike Zunino blocked numerous balls in the dirt and handled Montgomery on a day the lefty threw three wild pitches and walked three. But in the end, Montgomery did his part to help get Seattle snap a five-game losing streak to the AL West-leading Astros.
"I knew we had the lead and I wasn't quite as sharp as I would like to be, but I made good pitches when I had to," Montgomery said. "It's a win and our job is to not give up runs. Sometimes you don't have your best stuff, but you have to find a way to get it done."