Patrick Wisdom capped a big West Coast trip with a two-run triple, Eric Hosmer hit his first home run of the season and the Chicago Cubs spoiled the major league debut of Oakland Athletics pitching prospect Mason Miller with a 12-2, sweep-completing victory Wednesday afternoon.

Left-hander Justin Steele (3-0) remained unbeaten with six strong innings, helping the Cubs complete a 5-1 California swing, with the only loss being a walk-off defeat against the Los Angeles Dodgers on Saturday.

While the surging Cubs had been the story -- and the fans' favorite -- the first two nights of the series, all eyes Wednesday were on right-hander Miller, a 24-year-old former third-round pick who had demonstrated a propensity for strikeouts and 100-mph pitches in the minor leagues.

Miller touched 100 mph 15 times against the Cubs while working 4 1/3 innings, during which he allowed two runs and four hits. He walked one and struck out five, including Cody Bellinger, Edwin Rios and Wisdom in succession in the second inning.

He was pulled one out into the fifth after a sacrifice fly by Tucker Barnhart had given the Cubs a 2-1 lead. But he wound up with no decision after the A's tied the game in the bottom of the inning on Jordan Diaz's RBI double.

The Cubs dominated the final four innings, scoring four times against the Oakland bullpen in the sixth, once in the eighth on Hosmer's homer and five more times in the ninth on a bases-loaded double by Luis Torrens and two-run single by Nick Madrigal.

Wisdom's triple came as part of the tiebreaking sixth inning. He finished the game with two RBIs to wrap up a trip during which he had five homers and nine RBIs.

Chad Smith (1-1), who walked Dansby Swanson and Ian Happ to open the sixth, was charged with the loss.

Steele allowed both Oakland runs (one unearned) and four hits in his six innings. He walked two and struck out five.

Nico Hoerner had three hits, while Hosmer, Madrigal and Happ collected two apiece for the Cubs, who outhit the A's 11-5. Hosmer and Swanson scored three times apiece, while Bellinger and Happ each scored twice.

Carlos Perez had an RBI double for the A's, who were swept by both the New York Mets and Cubs on their just completed homestand. Oakland has lost seven in a row overall.

--Field Level Media