SEATTLE -- The Mariners overcame a rough “opener” as well as the Astros’ highly-regarded closer on Thursday, but they couldn’t quite pull off a win as Houston rallied in the 14th inning for a hard-fought 8-7 victory at T-Mobile Park.

The Mariners tied the game in the bottom of the ninth with Edwin Encarnacion's two-out RBI single off Astros closer Roberto Osuna, and again in the 10th with a solo blast by catcher Omar Narváez off hard-throwing Hector Rondon.

• Box score

But Houston answered both times, first on a bases-loaded sacrifice fly by Josh Reddick in the 10th and finally on a leadoff triple by rookie speedster Myles Straw in the 14th. He then scored on sacrifice fly by Yuli Gurriel for the game-winner off Matt Festa, Seattle’s eighth pitcher of the game.

Astros reliever Chris Devenski walked the bases loaded with two out in the bottom of the 14th before Shed Long flied out to left field to end the 5-hour, 6-minute contest.

The Mariners also walked the bases loaded with one out in the 11th, but came up empty.

It was Seattle’s first loss in five extra-inning games this season, and the 14 innings represented the Mariners’ longest game since a 15-inning win over the Tigers on Aug. 9, 2016. The time of game was the 12th longest in franchise history and longest since a 5-hour, 14-minute game in 2014 at Anaheim.

“Quite a ballgame,” Mariners manager Scott Servais said. “Our guys really competed their tails off today. I’m really proud of our effort in continuing to come back in the seventh, eighth, ninth, 10th inning -- all trailing. We keep fighting. Really great sign.

“There were a lot of good things offensively, and we played some pretty good defense. We had a couple chances to get that winning run across the plate. We just didn’t quite get it done at the end. But it wasn’t for lack of effort.”

Seattle rallied from a 5-1 deficit after Justin Verlander’s departure in the seventh to make things interesting, but in the end it was Houston headed home with a 3-1 series win and 43-21 record atop the American League West.

The Mariners finished their homestand 3-8 and are 26-40 as they embark on a nine-game road trip to Anaheim, Minnesota and Oakland.

It wasn’t an open-and-shut case

For the second time in their four-game series with the Astros, the Mariners employed the “opener” strategy. And for the second time, the ploy backfired early as reliever Austin Adams -- making his first Major League start -- gave up three runs right out of the gate.

“It was a great opportunity,” said Adams, who came into the game with a 2.79 ERA in eight appearances since being acquired last month from the Nationals. “I was really excited. Obviously the results weren’t there today. I just didn’t execute the two-strike slider today unfortunately, and just didn’t get the job done.”

Adams followed the same path as teammate Cory Gearrin, who allowed three runs in the first inning of Monday's 4-2 loss, before Wade LeBlanc pitched eight innings of one-run relief in that one.

“It didn’t work out the way we hoped it would,” Servais said. “I still think, strategically, it’s a good play for us right now. We just have to finish off the inning and put a zero up there, and we haven’t done that yet with the opener.”

This time around, Tommy Milone was fetched from the bullpen before Adams could even get out of the first, as he gave up three hits and two walks in two-thirds of an inning. Like LeBlanc, Milone performed well in the revamped relief role, allowing just one run on three hits over 5 1/3 innings.

“Tommy threw the ball well, kept them off balance and does what he does,” Servais said. “Again, the philosophy behind it -- we gave up three early -- but it did work. We were in the game and had a chance to win it, and had our bullpen pieces ready to go when we did catch up and tie them in the ballgame.”