ANAHEIM, Calif. -- Tyler Skaggs is finally performing like the pitcher the Los Angeles Angels drafted in the first round in 2009, traded away a year later and swiped back in 2013.

Skaggs threw seven shutout innings, and the Angels supported him with eight extra-base hits in a 9-1 victory over the Houston Astros on Wednesday night.

"I hope that Tyler can bottle this," Los Angeles manager Mike Scioscia said. "That's a tough lineup over there, and he couldn't pitch much better than he did against those guys."

Skaggs (2-5) allowed three hits, all in the first three innings, struck out five and walked one in an 85-pitch effort. The left-hander earned his first win since April 22.

"I didn't think too much out there," Skaggs said. "When I start thinking, that's when the wheels fall off."

Luis Valbuena homered in a five-run first inning. Justin Upton launched his first home run since he was acquired by the Angels on Aug. 31. It was the 250th homer of his 11-year career.

The Angels (74-71) remains two games behind the Minnesota Twins for the second American League wild-card spot. Houston (87-58) still has a magic number of five to clinch the AL West.

Los Angeles scored five runs in the first inning against Astros starter Mike Fiers, a replacement for Lance McCullers Jr. Arm fatigue caused McCullers to be scratched Tuesday from his scheduled Wednesday start.

The first inning started just the way it did against the Astros on Tuesday. In that game, Brandon Phillips led off with a line-drive double into the left field corner against Justin Verlander.

The big difference: Verlander didn't allow another hit in the next eight innings en route to a 1-0 victory. Against Fiers, though, the Angels followed with three more doubles and a two-run homer by Valbuena to take a 5-0 lead.

"The key is looking for a good pitch and be aggressive, too," Valbuena said. "Don't try to do too much and look for my pitch middle in."

Both benches were warned in the fourth inning by plate umpire Cory Blaser after Fiers threw a fastball about 5 feet over the head of Valbuena, who played the last two seasons with Houston and has gained notice for his celebratory bat flips after home runs and other productive at-bats.

"I took it as disrespect," Fiers said of Valbuena's first-inning bat flip.

Valbuena then doubled into the right field corner on the next pitch, C.J. Cron walked, Martin Maldonado sacrificed, and Phillips followed with a two-run single for a 7-0 lead.

Fiers was removed after Albert Pujols grounded an RBI single up the middle to make it 8-0. Fiers (8-10) went 3 2/3 innings and allowed eight runs and 10 hits.

The Astros lost center fielder Jake Marisnick to a right thumb injury after he was called out on a headfirst slide while trying to take second on a looper that fell into shallow right field in the third inning.

The ball trickled a short distance behind right fielder Kole Calhoun, prompting Marisnick to break for second. Angels first baseman Cron retrieved the ball and threw to shortstop Andrelton Simmons, who held the tag until Marisnick's fingers lifted slightly off the bag.

Marisnick flexed his hand as he walked off the field and was replaced in the bottom of the inning by Derek Fisher, who entered the game in left field as Cameron Maybin moved to center.

Marisnick is expected to fly home ahead of the team and have the injury examined.

"It doesn't look good," Astros manager A.J. Hinch said.

NOTES: Angels RF Kole Calhoun hit his 21st double of the season in the first inning. He is one of three right fielders in the majors with at least 20 doubles and 15 home runs each of the past four seasons, joining the Cleveland Indians' Jay Bruce and the Toronto Blue Jays' Jose Bautista. ... Andrelton Simmons hit his 36th double of the season in the first inning, second most in a season by an Angels shortstop behind the 45 by Orlando Cabrera in 2006. ... Astros RHP Collin McHugh threw an abbreviated bullpen session and isn't expected to make his next start until next week at the earliest. McHugh left after three innings against the Oakland A's on Friday after feeling discomfort from a fingernail issue. He was scratched from his scheduled Thursday start against the Angels.