"It was another step in the right direction," the right-hander said.
Fister (4-6) allowed one run on Albert Pujols' homer, struck out a season-high 10 and walked two for his third straight win.
He has had two stints on the disabled list this season with a strained left side, stunting his chances to follow up on what he did last year to help the Tigers win their division for the first time since 1987. Fister was 8-1 with a 1.79 ERA for Detroit after it acquired him from Seattle in a six-player trade nearly a year ago.
"Any time you take a hit or an injury, it's difficult to deal with," he said. "But at the same time, it's what makes you stronger, how you can mentally climb through something."
The Angels, meanwhile, hope starter C.J. Wilson can regain the form he had earlier this season.
Wilson (9-6) gave up a season-high seven runs on eight hits and five walks while striking out seven over six innings, extending his winless streak to four starts.
"I think it was just an anomaly," he insisted. "They hit a lot of grounders in the right spots, and a couple balls that landed just in front of our outfielders. Over the course of a season, those things usually even out."
The rough night might've given Wilson flashbacks. In his last start at Detroit -- for the Texas Rangers -- he gave up six runs in six innings of a 7-5 loss in Game 5 of the AL championship series.
"It looked like he couldn't get a feel for the baseball," Angels manager Mike Scioscia said. "He got behind, and that led to some walks and some hits. He's a pitcher that relies a lot on movement, and sometimes that means he will get behind hitters."
Pujols hit a two-out solo homer, his 17th, in the first inning to give Los Angeles its only lead -- which didn't last long. Delmon Young made it 1-all in the home half and extended his hitting streak to 10 games.
The Tigers provided Fister with more than enough run support in the second inning.
Brennan Boesch led off with a double, Gerald Laird drew a four-pitch walk and Ryan Raburn turned boos into cheers with an RBI single. Miguel Cabrera had with an RBI groundout and Fielder followed with a sharply hit single to left field that made it 5-1. Fielder is hitting .643 with runners in scoring position this month.
Boesch hit another double, driving in two runs, in the fifth to help the Tigers win for the ninth time in 11 games.
"We're starting to click a little bit," he said.
Tigers manager Jim Leyland was going to give Fister a shot at pitching a complete game, but changed course when he felt stiff.
"It was a no-brainer," Leyland said.
"We just didn't want to take any chances," he said. "It was a good call."
Pujols limped off the field after getting tagged out in the fourth inning and seemed to be favoring his left leg, but stayed in the game. "He's fouled a couple balls off of (his left foot), and he hit a base wrong in New York, so it bothers him from time to time," Scioscia said. "He just took a bad stride going down to second, and it bothered him a little. But our trainers have been checking him out and it isn't anything we are concerned about. Guys play nicked up all the time. He's fine." ... The Tigers plan to start Jacob Turner on Sunday against the AL Central-leading Chicago White Sox after he gave up seven runs in just two innings in a 13-0 loss to the Angels on Tuesday night. ... The Angels are hopeful that Vernon Wells and Chris Iannetta can take another step in their comebacks from the disabled list with rehab assignments this weekend. ... The Angels were encouraged by how Angels RHP Dan Haren (lower back stiffness) threw in a bullpen session Wednesday.
The San Diego Padres return to Petco Park Monday to start a homestand.
Shohei Ohtani's game-winning home runs was his first since May 17 and only his third hit in 17 at-bats since returning from the disabled list.
Kaito Yuki is headed to the Kansas City Royals organization instead of attending high school in Japan.
The New York Yankees can make up some ground on the first-place Boston Red Sox with a doubleheader against the struggling Baltimore Orioles on Monday at Camden Yards.
Shohei Ohtani's pinch-hit home run in the seventh inning sent Andrew Heaney and the Los Angeles Angels to a 4-3 victory over the Los Angeles Dodgers on Sunday.
Shohei Ohtani bashes his first career pinch-hit home run in which gives the Angels a 4-3 lead they would never relinquish in the seventh.