DETROIT -- Kyle Seager left Comerica Park with the first three-homer game of his career and he had no idea how it happened.
Seager homered in the fourth, sixth and ninth innings, driving in six runs as the Seattle Mariners beat the Detroit Tigers 11-6 on Tuesday night.
"I don't remember ever hitting three in a game at any level," he said. "I'm not sure I've ever done it."
Seager's first two homers were routine, but he got some help on the third one. His line drive to left-centerfield didn't have the distance to clear the fence, but centerfielder Niko Goodrum and leftfielder Brandon Dixon collided on the warning track. The ball hit Goodrum's glove and bounced over the fence.
"I was running, so I didn't see it," Seager said. "Everyone told me they knocked it over, but I'm going to have to find a replay online. When I tell the story, it's going to be a no-doubter."
Seager and Tom Murphy hit back-to-back homers in the fourth and sixth innings, but Tigers reliever Jose Cisnero walked Murphy in the ninth. No teammates have ever hit back-to-back homers three times in one game.
"That was a lot of fun," Murphy said. "I've never been a part of anything like that."
The Mariners won for the second time in 10 games, improving to 5-0 against Detroit this season. Zac Grotz (1-0) picked up his first win with 1 2/3 innings of relief.
Detroit lost for the ninth time in 12 games and fell to 16-42 at home. They need to go 6-17 in their final 23 games at Comerica Park to avoid becoming the first team to lose 60 home games.
Matthew Boyd (6-9) allowed seven runs on seven hits in 5 1/3 innings. He gave up four homers, and has allowed 30 this season, the third highest total in the majors.
"I take full responsibility for what happened - that game is on me," Boyd said. "I made a few bad pitches and they hit home runs in some big situations. I have to be better than that."
The Mariners took a 1-0 lead in the third on J.P. Crawford's RBI single.
Miguel Cabrera's ground-rule double tied the score in the bottom of the inning, but the Mariners regained the lead in the fourth.
Boyd retired the first two batters, but Seager and Murphy hit their first set of back-to-back homers to give Seattle a 3-1 lead.
"He just made some bad pitches," Tigers manager Ron Gardenhire said. "He's misfiring right now."
Detroit, though, regained the lead with two homers in the bottom of the inning. John Hicks led off with his eighth, and after Travis Demeritte singled, Jake Rogers hit the fourth of his career.
The homers were the 30th and 31st allowed by Yusei Kikuchi this season, tying him with Mike Leake for the major-league lead, one ahead of Boyd.
"He has to execute pitches, not throw the ball down the middle," Mariners manager Scott Servais said. "This is on him - he's pitched a long time and he knows what he needs to do."
Kikuchi only got one out in the inning before leaving with runners on second and third. The Mariners walked Cabrera to load the bases, but Grotz's wild pitch made it 5-3.
Jordy Mercer's RBI double gave the Tigers a 6-3 lead, but the Mariners answered with a six-run sixth that included Seager and Murphy's second set of back-to-back homers.
Seager's three-run homer tied the game and Murphy followed with a long homer to left to put the Mariners up 7-6. Nick Ramirez replaced Boyd, but allowed two more runs without getting an out.
Goodrum and Dixon's collision came three innings after they pulled up to avoid each other, allowing a ball to fall between them.
In both cases, Gardenhire felt Goodrum was at fault. Goodrum has started games at seven infield and outfield positions this season but had only played three full games in center field.
"Goody's been in the outfield plenty of times," Gardenhire said. "Guys are just trying to do too much."
RHP Brandon Brennan started the sixth inning for the Mariners, but left with pain in his left great toe after throwing two pitches. Sam Tuivailala replaced him and pitched a scoreless inning.
Murphy followed each of his two home runs with cartwheels in the dugout, something he's never done before and doesn't plan on doing ever again.
"This place has the biggest dugouts I've ever seen, and I said there was space to do a cartwheel," he said. "Then I said if I hit a homer, I was going to do one. I was rounding third when I realized I actually had to do it, and then I had to do one the second time."
Murphy does cartwheels with his daughter, who wasn't impressed.
"My wife texted me to say that my daughter said they were the worst cartwheels she had ever seen. She's kind of a perfectionist."
BOYD'S HOMER ISSUES
Boyd has allowed seven homers in his past two starts, giving him 19 in 11 starts at Comerica Park. Justin Verlander has the stadium record with 20 in 2016.
The teams play the second game of a three-game series on Wednesday evening, with Detroit's Edwin Jackson (2-5, 9.35) making his second start since returning to the Tigers. Marco Gonzalez (12-9, 4.25) is scheduled to pitch for Seattle.