Jabari Henry got the start in right field for Seattle and made the most of it, hitting a home run off Cashner in the fourth inning and an RBI single off Marcos Mateo in the seventh. Henry replaced Seth Smith, who was scratched with a sore ankle. Henry hit 30 home runs last season for High-A High Desert.
Seattle starting pitcher J.A. Happ, the Mariners' projected fourth starter after being acquired from Blue Jays, was hit hard by the Padres in his last start and struggled again Sunday. He allowed five earned runs on 11 hits in five innings, walking two and striking out three.
"I was being way too tentative early on," Happ said. "I just wasn't finishing and as aggressive as I was later in the game. Maybe trying to be a little too fine after the previous outing. I think if I throw like I did the second part of that game, I'll be OK."
Dustin Ackley hit a two-run home run in the seventh inning for his first of the spring.
Upton raised his spring average to .349 and also scored two runs. Catcher Derek Norris and Jedd Gyorko also notched a pair of hits.
Seattle's Burt Reynolds, in his first big league plate appearance of spring, tripled off Joaquin Benoit in the eighth to score Patrick Brady for the Mariners' fifth run.
Up Next For Mariners:Taijuan Walker, who hasn't allowed a run in 18 innings of Cactus League play, makes his sixth start for Seattle in a 1:05 p.m. PT game Monday against the Angels at Peoria Stadium. The 22-year-old right-hander appears to have earned the final spot in Seattle's rotation with a blistering spring in which he's allowed just six hits and four walks with 19 strikeouts. The game will be available on MLB.TV.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.