HOUSTON -- In the most brutally cruel way, the Mariners received the sourest taste of their own medicine in a walk-off, 8-7 loss to the Astros in Game 1 of the American League Division Series on Tuesday at Minute Maid Park.

Robbie Ray, in his first career save opportunity, surrendered a massive, three-run walk-off homer to Yordan Alvarez that spoiled what was shaping up to be another statement win on the road.

Ray was brought in to replace Paul Sewald, who hit No. 9 hitter David Hensley with a pitch, then surrendered a two-out single to Jeremy Peña that set up the big blast. One inning earlier, Andrés Muñoz surrendered a two-run homer to Alex Bregman that allowed the Astros to inch within two runs, after the Mariners had created separate four-run leads earlier.

Called on for a left-on-left matchup, Ray threw just two two-seam fastballs to Alvarez. The first the slugger fouled off swinging out of his shoes, and the second left his bat at a Statcast-projected 116.4 mph and traveled 438 feet into the second deck. Both were center-cut, the fateful one clocked at 93.2 mph out of Ray’s hand.

“I was just trying to get the sinker in on him, and it didn’t get there,” Ray said. “Just frustrating. I was ready. I felt fine. I felt good in the bullpen.”

The decision to go to Ray was brewing in the two days leading up to this moment, when the Mariners began mapping out their rotation -- specifically with the venue and opponent. Ray was battered to an 8.22 ERA in two starts in Houston, where the Astros slashed .371/.476/.771 (1.248 OPS) against him in 42 plate appearances. He also gave up six runs on 10 hits and lasted only three innings in a start against them in Seattle.

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Using Ray in relief illustrated that the Mariners probably didn’t intend to start their $115 million arm during this ALDS, even if he would not have been on turn again until Game 3 on Saturday in Seattle.

Unless the Mariners use George Kirby in Game 2, which is highly unlikely now given what’s transpired, the rookie will likely take that assignment. That would set up a return in Game 4 for Logan Gilbert, who outdueled Justin Verlander in Game 1, and Luis Castillo, who will start Game 2 on Thursday and could start Game 5 on short rest on Monday.

“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. “Bringing in a lefty against Alvarez, although Alvarez is one of the better hitters in the league ... I looked at it in the seventh inning and said, ‘Hey, this could happen.’ So that was the plan going in.”

Ray hadn’t pitched out of the bullpen since Sept. 29, 2020, and before that, since Oct. 4, 2017. In the regular season, he had made only two career relief appearances in '14; neither of those situations were in high-leverage spots. The only other lefty in Seattle’s ‘pen is Matthew Boyd, who has been a mid-leverage arm used in multi-inning pockets. The only other realistic option was leverage righty Erik Swanson.

“I pretty much knew that was kind of my pocket of guys, starting with Alvarez, from the beginning,” Ray said.

One game removed from their historic comeback in Toronto, the Mariners lost a game that was in the bag until, all of a sudden, it wasn’t. Making it more tough to stomach was that they chased Verlander after four innings and their offense was seemingly unfazed by this huge stage.

But once again, their house of horrors at Minute Maid Park chronicled another chapter, this one the ugliest yet. The Mariners are now 7-31 here since the start of 2019.

Opposing teams were 8-2 when scoring at least seven runs in this ballpark during the regular season, and Alvarez's walk-off homer was the first in postseason history with a player's team trailing by multiple runs.

“It's like a heavyweight fight,” Servais said. “You're going to get punched. It's how you respond in those moments and that's a tough one. Today, I thought we had it in hand. You’ve got to give them credit. Certainly, they’ve been in this spot many times before -- and you don't quit.”

Yet this one puts the Mariners on the precipice of the precarious. In the history of best-of-five postseason series, Game 1 winners have gone on to win the series 102 of 144 times (71%). In Division Series with the current 2-2-1 format, teams winning Game 1 at their home ballparks have advanced 34 of 47 times (72%).