Chas McCormick had three hits, including the tiebreaking home run in the eighth inning, as the visiting Houston Astros did just enough to beat the hapless Oakland Athletics 3-1 on Tuesday in the middle game of a three-game series.

Houston has won the first two games in the series and five of seven overall. On Tuesday, the Astros got five shutout innings from the bullpen.

Rafael Montero (3-0), the fourth Astros pitcher, got the win after handling the seventh inning. Ryan Pressley earned his ninth save, getting a double-play grounder to end the game.

Frankie Montas (2-5) took the loss despite a second consecutive strong outing. He allowed two runs on seven hits with five strikeouts and no walks in seven-plus innings. Oakland dropped its fifth game in the past six.

Houston was 11-10 and tied for second place with the Seattle Mariners when the month started. The Astros ended the month 32-18 and five games ahead of the Los Angeles Angels atop the AL West standings.

The Athletics got the scoring started in the fourth as Cristian Pache singled with two outs off Houston starter Cristian Javier, bringing home Elvis Andrus.

The Astros answered in the fifth, when Yordan Alvarez beat out an infield hit, moved to second on a single by Jeremy Pena and scored on two-out McCormick's single.

McCormick broke the tie and chased Montas with a solo home run to lead off the eighth. Zach Jackson relieved and walked four straight batters. The fourth, to Alex Bregman, sent home Jose Siri with a huge insurance run for the Astros.

Tony Kemp and Ramon Laureano had two hits each to lead the Athletics, who lost 21 games in May and have fallen to the bottom of the AL West standings. Oakland has won a major-league-low seven home games this season.

--Field Level Media