McCullers (4-1) did not surrender a baserunner until Oakland center fielder Mark Canha led off the sixth with a sharp single to center. Right fielder Stephen Piscotty added a single to right before McCullers induced a double-play grounder from catcher Bruce Maxwell and Matt Joyce followed with a harmless flyout to left. McCullers returned for the seventh and fanned the first two batters before getting designated hitter Khris Davis to fly out to center.

Since being tagged for a season-high eight runs at Minnesota on April 11, McCullers has allowed two runs over 20 innings and three starts. He struck out seven and did not walk a batter against the Athletics, who faced a right-handed starter for just the second time in eight games.

The Astros were handcuffed by Athletics left-hander Sean Manaea in the series opener on Friday night. They took out their frustrations against Oakland righty and Houston native Daniel Mengden (2-3), who failed to survive the third inning after allowing a pair of hits while already trailing 4-0. Alex Bregman capped a three-run first inning with an RBI double before Jose Altuve stretched the lead to four runs with a run-scoring single in the second.

Mengden surrendered five runs (four earned) on six hits and one walk over 2 1/3 innings. The Astros conducted their power surge against the Oakland bullpen, with Derek Fisher blasting a two-run homer to right off Athletics left-hander Danny Coulombe with no outs in the fourth.

George Springer and Altuve greeted right-hander Wilmer Font with back-to-back homers leading off the sixth, stretching the lead to 9-0. For Springer, it was his fifth home run; Altuve slugged his second homer and finished 4-for-5 with two RBIs, matching Hall of Fame first baseman Jeff Bagwell for second place in franchise history with his 26th career four-hit game.

The Astros last clubbed back-to-back homers on Aug. 18, 2017, against Oakland, with Bregman and Altuve doing the honors. Marwin Gonzalez added a solo home run in the seventh.

--Field Level Media