GOODYEAR, Ariz. -- Outfielder Norichika Aoki's RBI triple off Indians setup man Vinnie Pestano in the ninth gave the Brewers a 6-5 win in Cactus League action on Monday afternoon at Goodyear Ballpark.

Aoki is making the move from Japan to the U.S. Major Leagues and has gotten hot after a slow start. He began the spring 5-for-32 (.156) but has 11 hits in his last 17 at-bats, boosting his Cactus League average to .327 and leaving Brewers manager Ron Roenicke happily stumped about the reasons behind his turnaround.

"Wakaranai," Roenicke said Monday morning in Japanese.

I don't know.

"I really don't know," Roenicke said in English. "It's hard to make an assumption I really don't know."

Pestano is a right-handed pitcher, but Aoki has also shown a knack for hitting left-handers. He homered Sunday off Dodgers ace and reigning National League Cy Young Award winner Clayton Kershaw in a 10-pitch at-bat.

"This guy could end up being our 'right-handed hitter' on the bench, which sounds weird," Roenicke said.

Why does he handle lefties so well?

"The Japanese swing, there is a 'drift' to their swing," Roenicke said, meaning a player drifts forward with his body before actually pulling the trigger on a swing.

"He keeps his hands back so well," Roenicke said, "that even though he's drifting forward, he sees what the pitch is and his hands are still in the hitting position. ... He's just like Ichiro. They don't have to commit as early. The way most of the swings with our [American] guys are, you kind of need to make that commitment a little bit earlier."

Earlier in Monday's game, the Brewers broke through against Indians Opening Day starter Justin Masterson, but the Tribe delivered a handful of counter punches.

Masterson, who is scheduled to start against the Blue Jays when the Indians open the season at home on April 5, limited Milwaukee to one run over the first four innings before slipping in his final two frames. The sinkerballer stretched out to six innings -- his longest outing of the spring -- but allowed five runs in the process.

The Brewers struck for one run in the first inning, when Nyjer Morgan ripped a pitch from Masterson down the right-field line for a one-out triple. Slugger Ryan Braun followed with a run-scoring groundout to put the Indians behind early, 1-0. Masterson settled in from there until losing command of his sinker in the fifth.

Masterson opened the fifth inning with a walk to Edwin Maysonet, who later crossed the plate on a single from Braun. Brewers designated hitter Travis Ishikawa brought two more runs home with a double off Masterson to straightaway center field, pushing Milwaukee to a 4-1 lead. Taylor Green added an RBI double off Masterson in the sixth.

The RBI single for Braun was his second run-scoring hit of the spring.

"I like what I've seen out of him," Roenicke said. "I'm OK with what he's doing."

Brewers catcher George Kottaras, who started in place of Jonathan Lucroy, went 2-for-4 at the plate to improve to 11.-for-25 (.440 average) since his 1-for-12 start to the spring.

Brewers left-hander Chris Narveson -- the projected fifth starter -- yielded four runs on five hits in 6 1/3 innings against the Indians. He became the first Milwaukee pitcher to log at least six innings this spring, and continued a strong run for the club's rotation. The Brewers' projected starting staff has now combined for a 2.67 ERA this spring.

Up next for the Brewers: Yovani Gallardo will pitch against the Royals on Tuesday in his next-to-last start before a likely Opening Day assignment against the Cardinals. He will throw to catcher Jonathan Lucroy, who is reportedly close to a new multiyear contract extension. The Brewers also hope to have shortstop Alex Gonzalez back in the starting lineup after he missed the last two days with a bruised right heel.