CHICAGO — Adam Duvall won't soon forget his first at-bat with the Cincinnati Reds.

Called up from Triple-A Louisville earlier in the day, Duvall slugged a two-run go-ahead home run in the sixth inning to lead the Cincinnati Reds to Monday's 13-6 victory over the Chicago Cubs.

"It was exciting," said Duvall, who entered as a pinch hitter and launched a 2-2 pitch off Cubs right-handed reliever Justin Grimm to break a 5-5 tie. "There's something about the first day. I'm amped up and excited. I's a pretty cool feeling."

Duvall's shot also scored catcher Tucker Barnhart and capped a four-run inning.

"(Grimm) ended up making an elevated breaking ball mistake there and Adam didn't miss," said Cincinnati manager Bryan Price. "That was a big blow and we regained the lead there and it played big in our win."

The Reds (54-76) have now won two of their last three. The Cubs (74-56) have dropped five of their last six.

"Kind of a bad ending," said Cubs manager Joe Maddon, whose team didn't arrive from Los Angeles until early Monday morning. "It didn't start too good, the middle part of the book was actually a pretty good read and then eventually it became a nasty ending.

"I'm over it already. Just throw that one away."

Duvall, acquired by the Reds in a late July trade with the Giants, had spent the past month in Triple-A.

Cincinnati right-handed reliever Ryan Mattheus (2-4) pitched one-third of an inning for the win. Left hander Aroldis Chapman worked 1 2/3 innings for his 26th save.

Chicago right-hander Justin Grimm (2-4) pitched one-third of an inning in the sixth, giving up four runs on three hits for the loss.

The Reds exploded for six runs in the ninth, first loading the bases to chase Cubs left-hander Travis Wood with two out. Chicago second baseman Starlin Castro then bobbled a grounder, allowing right fielder Jay Bruce to score from third for an 8-5 lead.

Barnhart, who went 3-for-5, singled off left-handed deliver James Russell to score first baseman Joe Votto and pinch runner Ryan LaMarre to make it 10-5.

A Castro error on Chapman's grounder brought home shortstop Eugenio Suarez for an 11-5 lead. Center fielder Jason Bourgeois doubled to left to drive in Chapman and Barnhart as the lead reached 13-5.

Cubs second baseman Addison Russell homered with two out in the ninth to cut the final margin.

The Cubs led 1-0 in the third after center fielder Dexter Fowler's two-out solo home run to left. It was his career-high 15th.

The Reds punched across one run in the fourth. Cincinnati had runners on first and second with two out and left fielder Ivan DeJesus singled to shallow center to drive in first baseman Joey Votto from second and force a 1-1 tie.

The Reds scored twice more in the fifth for a 3-1 lead as second baseman Brandon Phillips' two-out base hit to left scored right-handed starter Michael Lorenzen and Bourgeois.

Chicago replied with four runs in last of the fifth.

Castro led off with a double, Kyle Hendricks was pulled for pinch hitter Chris Denorfia, who walked, and Russell lined a double with none out into the left-field corner to bring both home.

Catcher Kyle Schwarber then singled home Russell with one out to chase Lorenzen. Third baseman Kris Bryant greeted Mattheus with a two-out infield single to score Schwarber from second for a 5-3 lead.

Lorenzen, also called up Monday from Triple-A Louisville, worked 4 2/3 innings and allowed five runs on six hits, struck out five and walked one.

"I can live with that," Price said. "That's a game where he challenged hitters in the zone and they caught up to him in the fifth, but leaps and bounds better."

Hendricks allowed three runs on five hits in a five-inning outing. He struck out four and walked three.

"I thought he had really good stuff tonight," Maddon said. "I know he may like to have two pitches back, the one with the base hit up the middle with two outs and the base hit by Phillips, but I thought stuff wise from the side, good movement on the fastball. Some really good changeups, some really good hooks."

The lead was short-lived as the Reds forced a 5-5 tie in the sixth. Suarez homered to right off Grimm for his 10th of the season while also driving in DeJesus.

Duvall then clubbed his first home run of the season for a 7-5 lead.

NOTES: The Cubs acquired OF Austin Jackson and cash from the Seattle Mariners for an international signing slot and a player to be named. ... The Reds recalled RHP Michael Lorenzen from Triple-A Louisville and gave him the start Monday. Cincinnati also called up INF/OF Adam Duvall, who was acquired in the July trade that sent RHP Mike Leake to the San Francisco Giants. ... The Reds optioned LHP David Holmberg to Louisville and placed OF Brennan Boesch on the 15-day disabled list with a right ankle contusion. ... Cincinnati RHP Anthony DeSclafani (7-10, 3.84 ERA) against Chicago RHP Dan Haren (8-9, 3.90 ERA) on Tuesday. ... Cubs RHP Jake Arrieta was selected the National League Player of the Week after his Sunday no-hitter over the Los Angeles Dodgers capped a 2-0 week. ... Chicago wrapped up August with a 19-9 record. The Cubs are .500 or better in every calendar month this season.