With the division in hand, the Astros had another magic number to go after in the final regular-season series, and that was one win or a White Sox loss to ensure they'd have home-field advantage in the ALDS. Neither would come on Friday night, as Oakland would put together big innings to take the opener of the three-game series.

Final Score: A's 8, Astros 6

Astros' Record: 93-67, first in the AL West

Winning Pitcher: Sean Manaea (11-10)

Losing Pitcher: Framber Valdez (11-6)

Oakland tags Valdez with four runs

After a 1-2-3 first by Framber Valdez, Houston got on the board first in the bottom of the inning. A leadoff triple by Jose Siri set up an RBI single by Aledmys Diaz, making a 1-0 game. The one-run lead held until the top of the third, when a leadoff walk by Tony Kemp later turned into an RBI single, making it 1-1. Things got worse from there for Valdez, who allowed a go-ahead leadoff homer in the top of the fourth, then a two-run shot in the top of the sixth to end his night. His final regular-season line: 5.0 IP, 4 H, 4 ER, 1 BB, 7 K, 2 HR, 82 P.

Runs keep coming for the A's

Phil Maton was Houston's first reliever, retiring the three batters he faced after coming in for Valdez to finish the sixth. The Astros got one run back in the bottom of the inning, with a two-out walk setting up an RBI double by Jake Meyers to make it a two-run game.

Cristian Javier was next out of the bullpen, and he worked around a single for a scoreless seventh. Oakland figured him out in the eighth, though, putting up a four-run inning to push the lead back to six runs on a couple of errors and an RBI single and RBI ground-rule double.

Astros drop the opener

Jake Meyers notched his second RBI of the night in the bottom of the eighth, driving in Carlos Correa, who led the frame off with a single, making it 8-3. Jason Castros brought the Astros back to within two runs in the next at-bat, getting a three-run homer to cut the lead to 8-6. Yimi Garcia held the score there with a scoreless top of the ninth, sitting down Oakland in order, including two strikeouts.

Houston started a rally attempt in the bottom of the ninth, getting two on base to bring the winning run to the plate, but would come away empty as Oakland would take the opener. The White Sox winning earlier in the evening leaves the Astros magic number at 1 to clinch home-field in the ALDS.

Up Next: The middle game of this series will get started at 6:10 PM Central on Saturday. Paul Blackburn (1-3, 4.71 ERA) will be on the mound for Oakland, while Houston will hand the ball to Jake Odorizzi (6-7, 4.14 ERA).