HOUSTON (AP) — Yordan Alvarez wrecked all of Seattle's carefully crafted strategy with one colossal swing.

The Mariners came to the postseason with a plan. Down to their last out, the October-tested Houston Astros weren't so easily outmatched.

Alvarez smashed a game-ending, three-run homer with two outs in the ninth inning off Robbie Ray, foiling the Mariners' move to use a Cy Young Award winner in a rare relief role and vaulting the Astros to an 8-7 win Tuesday in their playoff opener.

"It was something going into the series where we were at, looking at our rotation, where we were going to head, and talking with Robbie about using him out of the bullpen as a bullet, so to speak, for that type of scenario," Mariners manager Scott Servais said. "You know, bringing in a lefty against Alvarez, although Alvarez is one of the better hitters in the league."

"But we talked about it coming into the series. We talked about it pregame today. I looked at it in the seventh inning and said, hey, this could happen. So that was the plan going in," he said.

Houston skipper Dusty Baker, who managed Servais while with the Giants, refused to second-guess his former player.

"If he gets him out, then it looks great ... next time Robbie Ray could win, but today we won," Baker said.

Trailing all game after a poor start by Justin Verlander, the AL West champion Astros overtook rookie star Julio Rodríguez and the wild-card Mariners at the end to begin their best-of-five Division Series.

The Astros had been 0-48 in their postseason history when trailing by more than a run after eight innings until Alvarez homered deep into the seats to overcome a 7-5 deficit.

With his Cuban parents in the stands, too.

"I think it's one of the most special moments that I've had in my career, having them there, and even for just the city of Houston," Alvarez said through a translator. "They know that we're a team that never gives up."

The no-doubt drive was the first walk-off homer in postseason history with a team trailing by multiple runs. And it was just the second walk-off homer with team down to its final out — the other was Kirk Gibson's startling shot that lifted the Dodgers over the A's in the 1988 World Series opener.

A stoic Ray said he was "just frustrated" after giving up the mammoth home run.

Houston rookie pinch-hitter David Hensley reached with one out in the ninth as Seattle closer Paul Sewald grazed his jersey with a pitch. Sewald struck out Jose Altuve before Jeremy Peña laced a single to center field to chase Sewald.

Servais then made the bold move to bring in Ray, who started Saturday at Toronto in the AL wild-card series, for a lefty vs. lefty matchup with Alvarez. Ray won the Cy Young last year with Toronto, had made only six relief appearances in his career and had never earned a pro save.

A percentage move — or was it?

Alvarez had a .998 OPS against left-handed pitchers this season, by far the highest among qualified left-handed hitters, and 10 home runs. And his batting average against lefties was .321, compared to .299 vs righties.

Alvarez, who hit 37 homers in the regular season, turned around Servais' move by launching Ray's second pitch into the seats in right field to set off a wild celebration with his mom and dad in the seats.

It was the first time they got to see him play in the postseason after arriving from the island in August to watch him play professionally for the first time.

The Mariners, back in the playoffs this year for the first time since 2001, were on the wrong end of a big comeback this time after rallying from a seven-run deficit in Game 2 to sweep their wild-card series with Toronto.

The Mariners jumped on Verlander for six runs in just four innings to build a 6-2 lead early. Yuli Gurriel hit a solo homer in the Houston fourth before Eugenio Suarez's solo shot in the seventh extended Seattle's lead to 7-3.

A two-run homer by Alex Bregman off Andrés Muñoz cut the lead to 7-5 in the eighth inning to set up the dramatic finish.

Alvarez had a two-run double in the third to get Houston's offense going a bit before it really took off in the final two innings.

The Astros, who are trying to reach the ALCS for a sixth straight season, led the AL with 106 wins but looked a bit out of sorts early after a six-day layoff since their last regular-season game.

"Those days off, I think hurt our whole team," Baker said. "You see, we didn't wake up until the fifth, sixth inning... you can practice all you want to. There's nothing, no substitute for game action. So that's not an excuse, but I can sort of feel it and see it."

They got going late to continue their dominance of the Mariners in Houston after going 30-7 against them in the regular season at Minute Maid Park since 2019.

Verlander followed up his remarkable comeback season after missing almost two full seasons after Tommy John surgery with a flop in the worst postseason performance of his storied career.

He led the majors with a 1.75 ERA and topped the AL with 18 wins this season. He dominated the Mariners in the regular season, going 5-1 with a 2.34 ERA in six starts.

Instead, the Mariners hit almost everything he threw in what was his 32nd playoff game. By the time he trudged off the mound mumbling something to himself after just four innings he'd given up a playoff career-high 10 hits with six earned runs, which tied his most in a postseason game.

"I have to do better next time out, but here we are with a Game 1 win and I couldn't be more happy," he said.

The last four batters Verlander faced hit, in order, a home run, triple, double and single.

Rodríguez tripled, doubled and scored three times and Ty France had three hits.

MATON OUT

Astros reliever Phil Maton revealed Tuesday that he broke his right pinkie when he punched a locker in frustration after Houston's regular-season finale and will miss the postseason.

Maton had surgery Monday to repair the fractured finger on his pitching hand.

The 29-year-old Maton gave up two hits, including a single to younger brother Nick Maton, and two runs while recording one out in the eighth inning of Houston's 3-2 win over Philadelphia last Wednesday.

UP NEXT

Seattle's deadline acquisition Luis Castillo, who got the win in the team's playoff opener at Toronto, opposes Framber Valdez in Game 2 Thursday in Houston.

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