HOUSTON -- Astros pitcher Wade Miley stayed in the dugout nearly the entire time, supporting his teammates and giving congratulatory high-fives for more than four hours while the Astros chipped away to try to erase a seven-run deficit he had helped create.

Despite having one of the worst starts of his career -- he didn¡¯t record an out while facing six batters -- Miley waited for a comeback. And waited and waited. The lefty had finally made his way to the clubhouse to finish watching the game on a television broadcast, which is delayed a few seconds from live action.

So when Miley heard the end-of-game fireworks boom through the clubhouse walls, he knew the day would end much better than it started.

Michael Brantley cranked a two-run, walk-off homer in the 13th inning to send the Astros to their biggest comeback victory in more than 25 years, beating the Mariners, 11-9, in 13 innings on Thursday night at Minute Maid Park.

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¡°That¡¯s what makes this team special, a never-give-up attitude and we¡¯re always in every game,¡± Brantley said.

The Astros improved to 13-1 this season against the Mariners, beating them for the eighth time in a row, while seeing their magic number to clinch the American League West reduced to 14. It was Houston¡¯s biggest come-from-behind win since wiping out an 11-0 deficit to beat the Cardinals, 15-12, on July 18, 1994.

¡°A lot happened in the game and obviously started out terribly for us but finished in dramatic fashion,¡± Astros manager AJ Hinch said.

Miley, who entered Thursday with the third-best ERA in the American League, failed to retire any of the six batters he faced and was rocked for a season-high five runs. He became the first Astros pitcher since Jim Clancy on Aug. 3, 1989, to not record an out without being injured or ejected.

¡°It¡¯s the best I felt in a month,¡± Miley said. ¡°They had me today. Tip your hat. Sometimes you get your butt whipped and I got my butt whipped.¡±

Here¡¯s how the Astros pieced together a comeback:

Starting from scratch

Trailing 7-0, cleanup hitter Yordan Alvarez reached on an error to start the second inning and scored on a wild pitch to get the Astros on the board. All-Star third baseman Alex Bregman gave the Astros life when he ripped a two-run double in the third inning, scoring Josh Reddick and José Altuve. For the season, Bregman has 98 RBIs, which is five shy of his career high set last year.

¡°They had seven runs before our cleanup hitter got to hit for the first time, so you have to stay in the game,¡± Hinch said. ¡°We just hung in there and kept chipping away and got some big swings and look up and we tied the game.¡±

Mariners 7, Astros 3

Tucker, Reddick hit big homers

Kyle Tucker, the Astros¡¯ top position-player prospect who¡¯s starting in place of the injured George Springer, led off the sixth with his first career homer. One out later, Reddick hit his first homer since June 28, snapping a 172-at-bat drought, to make a game out of it. Reddick went 3-for-3 with three runs scored.

¡°That was pretty surreal,¡± Tucker said. ¡°The whole crowd cheering and getting back in the dugout and everyone is super happy. That was awesome.¡±

Mariners 7, Astros 5

Altuve delivers

After Austin Nola hit his second homer, a solo shot in the seventh, Altuve followed a hit-by-pitch to Robinson Chirinos and a walk to Reddick with a two-run triple in the eighth, and then scored the game-tying run on a Brantley sac fly to left field.

¡°Being down early and the job the bullpen did, the job the lineup did to get us back in the game, it¡¯s a team effort all the way around,¡± Brantley said.

Mariners 8, Astros 8

Tucker drives in Straw

In the 12th, the Astros answered a second homer by Kyle Seager with a two-out RBI single by Tucker to score speedy pinch-runner Myles Straw from second base to tie the game again. Straw ran for Yuli Gurriel, who had walked.

¡°Another homer would be great, but you get a single right there and Straw can score,¡± Tucker said. ¡°He¡¯s fast enough to score on pretty much everything.¡±

Mariners 9, Astros 9

Brantley wins it

Brantley, who broke an 0-for-17 funk with a sixth-inning single, hit the first pitch he saw from reliever Matt Wisler in the 13th and sent it into the right-field seats to score Jake Marisnick for a two-run homer. It was his third career walk-off homer and career-high-tying 20th homer.

¡°Any win is a good win, especially this time of year,¡± Hinch said. ¡°Everybody is scoreboard watching, everybody is paying attention to what other teams are doing. It¡¯s a big win and it feels bigger because the month we¡¯re in and the countdown that we¡¯re having.¡±

Astros 11, Mariners 9