CINCINNATI -- Chicago Cubs left-hander Mike Montgomery believes his future in the major leagues is as a starting pitcher. Manager Joe Maddon agrees. On Wednesday night, Montgomery did nothing to dispel that notion.

Kyle Schwarber hit a three-run home run, Tommy La Stella added a two-run shot, and Montgomery allowed four hits through six innings, lifting the Chicago Cubs to their fifth straight win, a 9-3 victory over the Cincinnati Reds at Great American Ball Park.

Montgomery (4-6), who moved into the rotation when Jon Lester went on the disabled list, is considered a candidate to be in the starting rotation for the Cubs in 2018. For now, he is content with his role as a spot starter and reliever.

"Since day one I came over here, they've been telling me I'm a starter," Montgomery said. "I think I am as well. Whatever is best for the team, that's the mentality I've taken. That's how I've been able to transition back and forth."

On Wednesday, Montgomery issued one walk and struck out four. He retired 10 of the final 11 batters. His 89 pitches were the second-most he has thrown this season.

"He's a ground-ball machine," Maddon said. "Fastball command. When he gets ahead in the count, he can force hitters to put the ball in play. I'm not surprised by this at all. He's very capable."

Chicago (68-57) moved to a season-high 11 games over the .500 mark and now owns a season-high 3 1/2-game lead over second-place Milwaukee in the National League Central.

The Cubs played without third baseman Kris Bryant, who was hit on the hand by a pitch during the ninth inning on Tuesday night. But La Stella took over for Bryant at third base and went 1-for-2 with a homer, two RBIs and a walk. He reached base four times.

Cincinnati (53-74) has lost three straight games and has dropped nine of the past 12 series against Chicago.

Joey Votto hit a solo homer in the ninth, his 33rd of the season, off Hector Rondon, helping the Reds avoid their fourth shutout loss this season and third at home.

Cincinnati wasn't finished with Rondon, who allowed back-to-back homers by Eugenio Suarez and Scott Schebler before recording the final out.

It was the 24th homer of the season for both Suarez and Schebler.

"Rondon did what he's supposed to do in that situation," said Maddon. "Throw strikes."

Reds starter Asher Wojciechowski (3-3) needed 35 pitches to get through the first inning. He walked three, including La Stella with the bases loaded to force in a run.

Jason Heyward's RBI single coupled with a throwing error by Reds left fielder Adam Duvall scored two runs, putting the Cubs ahead 3-0.

"Helps when you get a three-run lead before you even go out there," Montgomery said. "The offense has been unbelievable for us the past week or so. Hopefully, we can keep it going."

Heyward came through again in the third when he drove home Anthony Rizzo, who had doubled, with another RBI hit, putting Chicago ahead 4-0.

Wojciechowski allowed eight runs (seven earned) in 3 2/3 innings.

"That first inning set the tone," said Reds manager Bryan Price. "He was up in the zone. You're in the first inning and you're down 3-0, there's not much room for error."

Montgomery induced 11 ground-ball outs, none bigger than one to end the third inning when shortstop Javier Baez made a sliding stab of Votto's hard grounder to start a 6-4-3 double play to end the inning after the Reds had runners on first and second.

"That was unbelievable," Montgomery said. "For him to backhand it, then for us to be able to turn the double play. Such a boost."

Schwarber then launched a three-run, opposite-field homer, his 21st of the season, to make the score 7-0. There was a 1-minute, 14-second crew chief review to determine the ball did clear the left field wall.

"That first half is a complete wash for me," said Schwarber. "I've felt a lot better at the plate recently, hitting the ball hard the last couple of days. Got to take those. Don't worry about the result, worry about the process and hit it where it's at."

Chicago led 9-0 in the fourth after La Stella hit a two-run homer, his third of the season, off right-hander Alejandro Chacin, who was making his major league debut.

"We grew from struggling in the first half," Montgomery said. "It's all about getting to the playoffs. We're completely over last year now. We're having fun."

NOTES: Cubs LHP Jon Lester threw on the side on Wednesday and is expected to throw a bullpen session on Friday in Philadelphia. Next steps will be determined after Friday's bullpen. Lester is on the disabled list with lat tightness and shoulder fatigue. ... Reds RHP Luke Farrell was recalled from Triple-A Louisville and RHP Alejandro Chacin had his contract selected from Louisville. The Reds also optioned OF Phillip Ervin to Triple-A, and RHP Blake Wood was designated for assignment. Farrell allowed one hit over three innings in his Reds debut.