OAKLAND -- Yonder Alonso notched his first homer of the season in thrilling fashion, launching a walk-off, three-run homer off Pat Neshek in the ninth inning for the A's, who also watched their top pitching prospect, Sean Manaea, make his big league debut in the 7-4 series-opening victory over the Astros at the Coliseum on Friday evening.
Stephen Vogt began the ninth with a double, and Mark Canha's ensuing sacrifice bunt advanced pinch-runner Tyler Ladendorf to third, at which point Coco Crisp was intentionally walked to bring Alonso, batting .174 this season, to the plate.
"I've been putting in extra work every single day to try to get back to what I know I can do," Alonso said. "Given the situation of the game and how we came back says a lot about our team. Just a good team win. We needed that.
"Flying around the bases, you get goosebumps running around. You just want to take it all in. Just speechless."
The A's trailed by two heading into the eighth inning but tied the game with right-hander Ken Giles on the mound thanks to a solo homer from Marcus Semien -- his team-leading sixth of the season -- and a sacrifice fly off the bat of Jed Lowrie after Billy Burns singled, stole second and advanced to third on an error.
"What's been consistent is every mistake we make has been magnified," Astros manager A.J. Hinch said. "They come back to haunt us."
Manaea was charged with four runs -- two of them scoring with lefty Sean Doolittle on the mound in a three-run sixth -- and four hits and four walks with three strikeouts in five-plus innings. Astros right-hander Mike Fiers strung together seven solid innings, his lone blemish a two-run homer to Coco Crisp in the second inning.
Evan Gattis homered for the first time this season to begin the second, and it was his RBI single in the sixth that tied the game and fueled the Astros to a three-run inning that also featured run-scoring hits from Tyler White and Marwin Gonzalez.
MOMENTS THAT MATTERED Who's not on third: Carlos Gomez hit a ball off the left-field wall to open the ninth inning and decided to go for three as the ball rolled away from left fielder Crisp. He never made it, getting thrown out by center fielder Burns and denying the Astros a chance to take the lead.
"It was extremely heads up to be over there in a position to make that throw," A's manager Bob Melvin said of Burns. "He's learning all the time. He was very impactful toward the later end of the game for sure."
Manaea arrives: Though his first big league pitching line left much to be desired, Manaea still managed to impress much of the night, facing the minimum in three of five full innings and showcasing a lively fastball throughout. Not once did he appear to be pitching with nerves, coming out of the gates with a nine-pitch first inning that ended with his first Major League strikeout. More >
"Obviously I thought he showed a lot of poise in his debut against a tough lineup," Vogt said. "I was joking, he got all the firsts out of the way first four hitters. First out, first hit, first punchout, first homer, and then he got to relax and go to work. He threw some really good pitches tonight."
Fiers goes seven: In his longest outing of the season, Fiers proved that by throwing strikes, good things can happen. He did not walk a batter. He threw 104 pitches and he probably only wanted one of them back, the home run ball to Crisp. More >
"We would've taken anything in the outfield grass, but right-field bleachers work too." -- Melvin, on Alonso's home run
WHAT'S NEXT Astros: Right-hander Chris Devenski (0-0, 0.66) gets his first start of the season in Saturday's 3:05 p.m. CT game against the A's. He has 12 strikeouts in 13 2/3 innings against one walk as a reliever. The 25-year-old rookie has given up 11 hits.
Athletics: Right-hander Jesse Hahn will be recalled from Triple-A Nashville on Saturday to make his 2016 A's debut in a start against the Astros, with first pitch at the Coliseum set for 1:05 p.m. PT. Hahn, who posted a 3.35 ERA in 16 starts for Oakland last year, had a 2.04 ERA in four starts for the Sounds.