HOUSTON — Oakland's Ryon Healy doesn't love how he's feeling at the plate these days.

"Oh man, I feel terrible right now," he said. "Have you guys seen my at-bats the last week? They're not pretty."

Amid his struggles, he found a huge bright spot on Tuesday night, hitting his first career grand slam to break a tie in the sixth inning and the Athletics held on for a 6-4 victory over the Houston Astros.

"Oh, that was his first (grand slam)? He about broke my hand, I should have known," manager Bob Melvin said. "It seems like every magnitude homer for him he gets a harder hand slap."

The score was 1-1 when Matt Joyce singled to start the sixth. Jed Lowrie singled with one out before Yonder Alonso drew a walk with two outs to load the bases and chase Mike Fiers (5-3). He was replaced by James Hoyt, who was greeted with Healy's 18th homer — a full-count shot which landed in the second row of the seats in right field to put the Athletics up 5-1.

Sean Manaea (7-4) allowed a season-high nine hits, but just one run in 5 2/3 innings for his first win over the Astros in seven starts.

"It seemed to be (that) every inning we were on the cusp of breaking through against Manaea, and we couldn't quite pull it off," Astros manager A.J. Hinch said.

The victory is the fourth straight for the Athletics and just their second against Houston in the last 17 games.

George Springer hit a three-run homer off Liam Hendriks with no outs in the ninth to cut the lead to 6-4. Santiago Casilla took over and allowed singles by Jose Altuve and Carlos Correa before pinch-hitter Josh Reddick popped out and Brian McCann grounded into a double play to give Casilla his 14th save.

Fiers, who had gone 4-0 with a 1.72 ERA in his last five starts, allowed four hits and four runs with seven strikeouts in 5 2/3 innings for his first loss since May 20.

Khris Davis scored in the second and added an RBI double in the eighth to make it 6-1.

Davis was hit by a pitch to start the second and stole second base. He advanced to third on a wild pitch by Fiers with one out before the Athletics took a 1-0 lead when he scored on a single by Bruce Maxwell.

The Astros had at least one runner on base in each of the first four innings but weren't able to push any runs across. In the fifth Springer and Altuve hit consecutive singles with no outs before Correa walked to load the bases. The Astros tied it at 1-all when Evan Gattis grounded into a double play which scored Springer.

TRAINER'S ROOM

Athletics: Melvin said that they aren't sure if RHP Jharel Cotton will be able to start on Thursday because of a blister on his right thumb. Melvin said he would know on Wednesday if they need to push his start back. ... SS Marcus Semien (right wrist surgery) is on a rehabilitation assignment with Single-A Stockton. Melvin said Semien, who has been out since April 15, will be off on Wednesday before increasing his playing time to nine innings on Thursday. He'll likely need between 35 and 50 at-bats in the minors before coming off the DL.

Astros: RHP Collin McHugh, who hasn't played all season because of an elbow injury, is scheduled to make a rehabilitation start for Double-A Corpus Christi on Friday. McHugh will need several starts in the minors before he's ready to come off the DL and likely won't pitch for the Astros until after the All-Star break. ... RHP Charlie Morton (strained back muscle) allowed two hits and no runs in four innings in his second rehabilitation start for Triple-A Fresno on Tuesday night.

SUPER SPRINGER

Springer's home run was his 23rd this season which is the most by an Astro before the All-Star break since Lance Berkman had 24 in 2006. His 23 homers rank second in the American League behind New York's Aaron Judge, who has 26.

UP NEXT

Athletics: RHP Jesse Hahn (3-5, 4.66 ERA) is scheduled to start for Oakland on Wednesday. Hahn is 2-1 with a 7.00 ERA in four starts since he came off the DL on June 6.

Astros: RHP David Paulino (2-0, 5.04 ERA) will start for Houston on Wednesday. The rookie's last start was also against Oakland, when he allowed seven hits and three runs in 5 1/3 innings, but did not factor into the decision in a 12-9 win on Thursday.

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