SEATTLE -- This day, two decades in the making, seemed like it was never going to end. Game 3 of the American League Division Series between the top-seeded Houston Astros and Seattle Mariners, hosting their first postseason game since 2001, featured epic pitching, exemplary defense and, finally, in the 18th inning, the only hit that mattered.

Rookie Jeremy Pena's solo home run off Mariners reliever Penn Murfee provided the lone tally in Houston's 1-0 victory that cinched a spot in the AL Championship Series for the sixth consecutive season. Never before had a postseason game gone scoreless for as long as Game 3. Its 18 innings tied a postseason record with three other games, its 6-hour, 22-minute run time the third longest ever. The 42 strikeouts recorded by both teams set a record. The four combined walks and no errors exemplified that this wasn't just battle of offensive ineptitude but rather a clinic in run prevention.

It was the capper of an oxymoronic outcome: The close sweep. While Houston took all three games in the best-of-5 series, comeback victories in Games 1 and 2 showed that the Mariners were no fluke. They were simply not good enough to overcome Houston's deep pitching staff and dangerous lineup.

"We kept putting the zero up there and they kept putting the zero up there and you think we're going to be able to break through because we have so many times," Mariners manager Scott Servais said. "It's kind of what we're accustomed to, playing those tight games and finding a way. ... I mean, that is a big league game, with the pitching and defense that was fired out there. We just weren't able to put anything together."

In the game's first half, the story centered around a pair of great starting pitching performances, by Seattle rookie George Kirby and Houston right-hander Lance McCullers Jr., who was battling an illness. Kirby threw seven brilliant shutout innings; McCullers nearly matched him with six. Each ceded to a bullpen that ranks among the best in baseball, something both showed as arm after arm entered and exited the game without allowing a run.

Seven Seattle relievers put up scoreless outings. Houston matched that number, led by Luis Garcia, the right-handed started who finished with five shutout innings, allowed two hits and no walks, struck out six and locked down the 18th to earn the victory.

Pena, the 25-year-old rookie who took over at shortstop upon the free agent departure of Carlos Correa, had provided the necessary run in the top of the inning. He entered the at-bat 0-for-7. He left it 1-for-8 after Murfee hung a slider and Peña pummeled it out to center field.

"You could tell by his brightness in his eyes and his alertness on the field that he wasn't scared and he wasn't fazed by this," Astros manager Dusty Baker said. "Boy, he's been a godsend to us, especially since we lost Carlos, because this could have been a disastrous situation had he not performed the way he has."

Houston's offense, the best in the AL this season, managed just 11 hits in 63 at-bats. Seattle's offense, which lived by the home run this season, was 7-for-60. The Mariners struck out 22 times and drew three walks. The Astros walked just once against 20 punchouts. The defense was clean, none better than when Mariners star rookie Julio Rodriguez tracked down a Yuli Gurriel shot into the right-center-field gap in the 16th to save a pair of runs.

All night, "Ju-li-o" chants permeated T-Mobile Park, which 47,690 packed to see the Mariners' first playoff team since the 2001 group that won 116 regular-season game but lost in the ALCS. While this Mariners core is likely to return to the playoffs in the coming years, the Astros are still the team through which the AL runs.

With a thin bullpen hamstringing them in past seasons, the Astros focused on sharpening it this year and after McCullers ran out a litany of power-armed relievers who each threw a scoreless inning: Hector Neris, Rafael Montero, Ryan Pressly, Bryan Abreu and Ryne Stanek. Rookie Hunter Brown put up a pair of scoreless frames. And then came Garcia's command performance.

"This at-bat," Pena said of his home run, "was not going to be possible if our pitching staff didn't keep us in the ball game. They dominated all game. Their pitching staff dominated all game."

The game resembled another from earlier this postseason, when Cleveland and Tampa Bay were scoreless until the 15th, when rookie Oscar Gonzalez hit a walk-off home run to clinch the wild card series for the Guardians. Excellent pitching has been the key for Houston, Philadelphia and San Diego, all of whom have advanced. Cleveland can grab the final championship-series spot and face the Astros with one more victory against the Yankees.

"We're expecting more of the same," Baker said, and it's certainly a reasonable expectation. Since MLB expanded to divisions in 1969, no team has advanced to the ALCS six consecutive times. The Astros started their run by winning a championship in 2017, lost World Series in 2019 and 2021, and will be favorites to go back again, coming off a 106-win season and remaining the only playoff team this season without a defeat.

Even better for the Astros, the sweep allows them to reset their rotation instead of using ace Justin Verlander in a potential Game 4 against Seattle. With the ALCS set to begin Wednesday, Verlander and the Astros' No. 2 starter, Framber Valdez, can pitch on extra rest.