HOUSTON -- Bryce Miller craned his neck to the sky after unleashing his 97th and final pitch on Monday night, circling the mound then pursing his lips as he clenched his pitching fist before pounding his chest three times.

For the affable right-hander who rarely shows emotion on start days, it was a gesture of exhalation after clearing the only real jam in a 6-1 win over the Astros that was far more tense in the early stages than the box score would indicate, thanks to Seattle’s four insurance runs late.

“Added pressure doesn't help anybody,” Miller said. “You can use the pressure to your advantage, get the blood flowing a little more, get some adrenaline. But at the end of the day, you’ve got to go out and execute and have fun. And it's always fun pitching here.”

In his final sequence, Miller stranded runners on second and third base with the go-ahead run at the plate, besting Victor Caratini with a strikeout on eight pitches then Jeremy Peña on four -- turning to his splitter for strike three on each.

“He was almost unhittable today,” Astros star Jose Altuve said.

Miller had more than 20 family members and friends in attendance from his hometown in nearby New Braunfels, Texas, including his grandfather, who’d never seen him pitch in the Majors. And that group witnessed a Texas-sized performance, as Miller almost single-handedly spoiled what the Astros were hoping would be a night of celebration in claiming their seventh American League West title in the past eight years.

The Mariners, meanwhile, badly want to keep that champagne on ice before they leave town, and in a perfect world -- albeit an unlikely one -- those bottles never get popped. Houston needs just one win in this series to claim the division crown. Seattle (81-76) needs to essentially win out and get help from the Guardians when they host the Astros this weekend to keep its division title hopes alive, as the Mariners pulled to four games behind Houston in the AL West with five games to play.

In the AL Wild Card race, each of the other three contenders -- the Tigers, Royals and Twins -- were idle on Monday, allowing the Mariners to pull to 1 1/2 games back of the final spot. But they don’t own a tiebreaker against any of those clubs, meaning that they’ll need to finish one game better than two of the three to get in.

“We're focused on us, on our clubhouse, one win at a time,” Miller said. “And we're gonna try to see what we can do.”

Miller threw seven shutout innings and only allowed four baserunners -- via two singles and two walks, including one apiece in that tense seventh inning.

Alex Bregman drew a free pass on eight pitches then Yainier Diaz poked a single through the right-side hole. Then, Miller fielded a grounder by Jon Singleton but was unable to nab the lead runner at third when Dylan Moore didn’t make it to the bag in time and instead had to go to first. It led to an out but advanced the runners into scoring position and brought the tying run to the plate.

And that’s where the second-year starter zeroed in and punctuated his outing. In the process, Miller lowered his ERA to 2.94, but over his past 15 starts, it’s 1.94. And he did so despite experiencing back tightness while doing plyometric warmup exercises.

“I knew it was a big game, and we needed to win today,” Miller said. “So I just had to go out and do what I could.”

The Mariners’ four insurance runs were manufactured after Miller departed, creating enough cushion for manager Dan Wilson to avoid using Andrés Muñoz for the second day in a row. Houston’s lone run also came after Miller departed, when Jason Heyward took rookie Troy Taylor deep in the eighth.

But Taylor was warming as Miller labored through his jam, putting Wilson in a decisive quandary on the dugout’s top step.

“These are the tough decisions,” Wilson said, “but when you saw what Bryce was doing and the way he was rolling and the moment that he was in, it's pretty clear in some ways also.”

The Mariners have now won seven of 11 vs. the Astros this season and are 3-1 in a venue that for years was their house of horrors. They’ll need to continue to channel that mojo at Minute Maid Park to keep their playoff hopes alive.