SEATTLE — Rookie Michael Busch homered for the fourth straight game, Javier Assad struck out six and the Chicago Cubs beat the Seattle Mariners 3-2 on Sunday.

Reliever Adbert Alzolay picked off pinch-runner Julio Rodríguez to end the game after double plays ended two rallies. First-base umpire Doug Eddings initially called Rodríguez safe under first baseman Busch’s tag, but Alzolay knew the call would be overturned.

“I was kind of playing with the clock a little at that time,” Alzolay said. “As soon as I seen him kind of jumping, that’s when I made my move. … I was super confident. As soon as I threw the ball, I saw Buschy (making the tag) and looking at his face, he goes, ‘Oh, yeah, I got it.’”

Busch’s two-run homer put the Cubs up 3-0 and helped them to their second straight win to take the series from the Mariners. The franchise record for consecutive games with a home run is five, held by four players, including current Cubs slugger Christopher Morel, who did it last season.

“He’s hit four homers in four straight games,” Cubs manager Craig Counsell said. “You don’t say that very often about anybody. So, for sure, (it’s amazing) having a first-year player do it, who’s really kind of driving the bus for us offensively the last couple of days.”

The Cubs scored their only other run on a first-inning throwing error by Seattle starter Luis Castillo (0-4), who lost his fourth straight appearance to start the season.

Jorge Polanco hit a two-run homer in the sixth to cut Chicago’s lead to 3-2, chasing Assad (2-0). Assad struck out six and walked one in 5 2/3 innings.

The Mariners put two on with no outs to lead off the seventh, but Mark Leiter Jr. induced a grounder from Luke Raley for a 6-4-3 double play to end the threat.

Héctor Neris walked three to load the bases with one out in the eighth, but Ty France grounded to short for a second rally-killing 6-4-3 double play.

“They gave us the opportunities to go get the game and the series, and we just didn’t go grab it,” Mariners manager Scott Servais said.

Of the game-ending pickoff, Servais said: “It happens, but for me that’s not the play that cost us the game.”

Alzolay struck out two to earn his third save in five opportunities.

Castillo had his best outing of the season, reaching six innings and holding opponents to fewer than four runs for the first time. But his errant throw while chasing down Cody Bellinger’s bouncer down the first-base line allowed Seiya Suzuki to score easily from third.

“I just feel like we’re coming together as a whole right now,” Alzolay said.

Mariners LF Dominic Canzone left in the second inning after injuring the AC joint in his left shoulder on a spectacular catch at the wall. Canzone ran down Nico Hoerner’s line drive to the left-field gap and slammed face-first into the wall as the ball hit his glove. He made a quick seated throw to second to hold a runner, then lay sprawled on the warning track for a few moments. He walked off the field gingerly and was replaced by Dylan Moore.

Servais said after the game the Mariners would likely have to make a roster move.

Rodríguez was given the day off before he entered as a pinch runner in the bottom of the ninth for C Cal Raleigh. Servais characterized it as a rest day for the struggling third-year player. The two-time All-Star is batting .186 with a 33.3% strikeout percentage.

Cubs right-hander Ben Brown (0-0, 6.10) takes the mound to start a three-game series at Arizona. He has allowed one run in his last 8 2/3 innings.

Seattle Mariners second baseman Jorge Polanco (7) catches Chicago Cubs designated hitter Seiya Suzuki trying to steal second during the fifth inning of a baseball game Sunday, April 14, 2024, in Seattle. (AP Photo/Lindsey Wasson)

Chicago Cubs starting pitcher Javier Assad throws against the Seattle Mariners during the fourth inning of a baseball game Sunday, April 14, 2024, in Seattle. (AP Photo/Lindsey Wasson)

Chicago Cubs’ Michael Busch jogs home after hitting a two-run home run against the Seattle Mariners during the fourth inning of a baseball game Sunday, April 14, 2024, in Seattle. (AP Photo/Lindsey Wasson)