SEATTLE -- Gloom appeared to be reaching doom for the Mariners from the get-go on Tuesday night, as George Kirby labored himself into a bases-loaded jam in the first inning. Seattle’s playoff push has been in peril in this defining stretch of its season, and an early Astros onslaught would make a worst-case scenario even more painstakingly unimaginable.

Kirby had just issued his first career intentional walk after falling behind 3-0 to Kyle Tucker, at which point the uber competitive righty exhaled and awaited the call from catcher Cal Raleigh. He then attacked José Abreu with the sinker/slider combination that came to define his outing, inducing a critical forceout at the plate ignited by another stellar play from Eugenio Suárez in a season full of them. Five sliders and another groundout later, Kirby was off and running.

Crisis averted. Stage set. And on the heels of one of the most challenging stretches of his young career, Kirby was dialed in for a masterpiece.

Seattle’s first-time All-Star wound up clearing six shutout innings, which -- coupled with timely run production that the Mariners’ offense has lacked in this September swoon -- lifted the club to a 6-2 victory over Houston at T-Mobile Park. Their postseason hopes are still far from realized, but also far from over.

• Games remaining (5): vs. HOU (1), vs. TEX (4)
• Standings update: The Mariners (85-72) pulled to within three games back of the Rangers (88-69) for first place in the AL West and a half-game behind second-place Houston (86-72), which holds the third and final AL Wild Card spot. Toronto (87-70), which also lost on Tuesday, is 1 1/2 games up on Houston for the second AL Wild Card spot. The Mariners are the first team on the outside looking in.
• Tiebreakers: Win vs. Houston (9-3); lose vs. Texas (1-8); likely win vs. Toronto (3-3, tiebreaker based on intradivision record).
• Path to postseason: If the Mariners win the series finale then split their four-gamer against Texas, Houston would need to sweep Arizona -- which is fighting for an NL Wild Card spot -- to keep Seattle out.

“We've been scuffling here the last four days and you start to wonder, 'Can we get it going again'?” manager Scott Servais said. “'When are we going to get it going again?' A heck of a job by George tonight.”

Kirby carved through the Astros with clean innings from the second through fourth to reallocate his pitch count to 55 and position him to clear the sixth on a night in which Servais’ highest-leverage relievers were all well rested. Kirby allowed just three hits after the first inning (of five total), and only once the rest of the way did a runner reach scoring position.

His attack to Houston’s righty-stacked lineup was simple yet deliberate: sinkers in on the hands and sliders off the plate away. It steered from the swing-and-miss approach that’s defined his young career, but the necessary adjustment paved the way for nine groundouts, zero extra-base hits and none of the 18 batted balls against him exceeding 98.1 mph.

"They don't like the ball inside, so just keep feeding them inside and play the slider off it,” Kirby said. "I'm really glad I executed tonight with both of those."

Kirby’s sinker/slider combo was the headliner in this vital victory, but Matt Brash was just as effective.

Taking over with no outs in the seventh after Justin Topa loaded the bases, Brash surrendered a sac fly to Jon Singleton that scored Houston’s first run, before buckling Jose Altuve with a front-door slider inside and retiring Alex Bregman on a forceout to end the inning.

Sent back out for the eighth after just 10 pitches, Brash retired Yordan Alvarez on a flyout and José Abreu on a comebacker and nabbed Yainer Diaz on a breaking ball above the upper rail. In between, he worked around a double to Kyle Tucker to escape unscathed, a sequence that’s at times been challenging.

Brash leads the Majors with 76 appearances, and now has 105 strikeouts in 69 innings.

“Where would we be without him? I don't want to think about it,” Servais said.

Seattle’s blueprint has always been rooted in pitching, but operating with an early lead proved just as essential on Tuesday. During its four-game losing streak, it had only led once and for a half-inning. And Houston entered play 61-22 when scoring first this season, MLB’s fourth-best record.

The Mariners struck first thanks to the wheels of unlikely speedsters, Mike Ford and Ty France. Ford walked home in the third after an error on a relay throw from Altuve sailed into the dugout when he tagged from second on a flyout, while France raced to the plate on a sacrifice fly from Julio Rodríguez, dialing his sprint speed up to 26.7 feet per second -- his fastest tracked time of the year.

France also crushed a punctuating homer in the eighth, his first since Aug. 15 amid a brutally tough stretch.

In between, Seattle added three tallies after chasing Cristian Javier in the fifth, when Cal Raleigh dumped an RBI single into right that also featured a throwing error from Kyle Tucker, plating another run.

The Mariners badly needed a rebound from their rotation, which carried an 8.85 ERA during this losing streak, and just as much, a punch-back from their offense after a lifeless series opener.

With both, their trajectory has swung swiftly.