Lux pounded his chest and gestured to his dugout while his first homer of the season landed in the right-field bleachers for the defending World Series champions, who opened a nine-game homestand with just their sixth win in 21 games.
Lux has struggled to keep his batting average above .200 during his injury-plagued start to the Dodgers' rocky season. His cathartic celebration showed just how much the homer meant to the up-and-down infielder and his teammates.
''That kind of takes the cake,'' Lux said. ''I don't really know where that came from, to be honest with you. That's by far the most emotion I've shown. Just talking to some guys, we definitely need that, for sure.''
Max Muncy hit an early homer for the Dodgers, who trailed 4-1 in the seventh before Corey Seager came through with a two-run single.
Lux then delivered the game-changing hit the Dodgers have lacked lately off Rafael Montero (3-2). The Seattle closer had escaped a tough jam in the seventh.
''All wins are important, but they're not created equal,'' Dodgers manager Dave Roberts said. ''Gavin has been grinding, so for him to get that hit was big for our ballclub. I think there was some semblance of a beer shower in there.''
Mitch Haniger hit two solo homers and Kyle Seager added a two-run shot for the Mariners, who have lost three straight on their five-game road trip.
Garrett Cleavinger (1-3) pitched a perfect eighth for the 27-year-old reliever's first major league win. Kenley Jansen worked a flawless ninth for his sixth save.
Seattle couldn't capitalize on a strong start by Yusei Kikuchi, who racked up a career-best 11 strikeouts while pitching six-hit ball into the seventh inning.
''He continues to get better and better, and just build as the season goes along,'' Mariners manager Scott Servais said. ''Unfortunately, we weren't able to lock it down there. Thought we had enough to hold them off, but Yusei certainly deserved a better fate tonight.''
Kikuchi outdueled Walker Buehler, who gave up homers for three of the four hits he allowed over seven innings while striking out eight.
Kyle Seager lofted a high homer to right off a good inside cutter from Buehler in the fourth, putting Seattle up 3-0 with his third career homer at his younger brother's home ballpark.
Muncy's 433-foot homer in the fourth was his sixth of the season.
After the Dodgers loaded the bases and chased Kikuchi in the seventh, reliever Anthony Misiewicz got a generous called third strike on Mookie Betts before Corey Seager's two-out single trimmed Seattle's lead to 4-3.
Haniger connected for a 402-foot homer in the first inning and another shot in the sixth.
His third career multi-homer game, his first since June 2018, gave him a team-leading 10 home runs this year and evoked memories of the power he showed off during his All-Star campaign in 2018, when he hit 26 homers in his only full major league season.
''I feel good,'' Haniger said. ''Over the weekend, I didn't feel too good, so I came in and did some work. It's always a work in progress.''
Improbably, Lux's homer was the first of his career in a regular-season game at Dodger Stadium. The infielder cracked the Dodgers' roster in 2019, but he hadn't homered in his first 29 regular-season games at home.
Lux did homer at Chavez Ravine in his first postseason at-bat two years ago.
Dodgers: AJ Pollock drew a pinch-hit walk in the seventh, his first action since straining his hamstring Friday in Anaheim. ... Cody Bellinger is ''progressing nicely'' in his return from a hairline leg fracture, Roberts said. Bellinger is still running at 60%. ... LHP David Price (strained right hamstring) threw a simulated inning. He will be activated after he throws to hitters once or twice. ... RHP Tony Gonsolin (right shoulder inflammation) will throw two innings in Arizona this week. He will make minor league rehab starts before he returns.
Los Angeles LHP Julio Urias (4-1, 3.59 ERA) takes the mound for the series finale against RHP Justin Dunn (1-0, 3.51). Urias has gone five innings in all seven starts this year, but he was roughed up by the Angels for five runs last Friday.
More AP MLB: https://apnews.com/hub/MLB and https://twitter.com/AP-Sports
Copyright 2021 STATS LLC and Associated Press. Any commercial use or distribution without the express written consent of STATS LLC and Associated Press is strictly prohibited.