CHICAGO -- Kris Bryant homered high off the left-field video board and tied a club rookie record for RBI, Miguel Montero hit a grand slam, and the Chicago Cubs beat the Arizona Diamondbacks 6-4 to complete a three-game sweep Sunday.

Bryant's drive leading off the fifth against Rubby De La Rosa (12-7) traveled an estimated 495 feet. It also gave him 86 RBIs, tying a club rookie mark held by Hall of Famer Billy Williams (1961) and Geovany Soto (2008), and wiped out a 1-0 deficit.

Montero connected against Matt Reynolds in a five-run sixth. Pinch-hitter Jonathan Herrera added a solo drive off Silvino Bracho in the inning to make it 6-1, sending Chicago to the victory.

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The schedule is about to get tougher for the Cubs -- tops in the National League at 26-10 since July 29 -- with three games at Central leader St. Louis starting Monday. But they did exactly what they wanted in this series after dropping six of eight.

Former Cub Welington Castillo had three hits, including an RBI double in the fourth and a solo home run in the ninth. Nick Ahmed added a two-run drive off Pedro Strop in the inning before Phil Gosselin struck out, giving the Diamondbacks 11 losses in 14 games.

De La Rosa gave up three runs and five hits in five innings.

Justin Grimm (3-4) picked up the victory with a scoreless inning in relief, and Kyle Hendricks remained winless since Aug. 8. He held Arizona to just one run and three hits before being lifted for a pinch hitter in the fifth.

Bryant drive leading off the fifth gave him 23 homers -- two shy of Williams' franchise rookie mark.

TRAINER'S ROOM

Diamondbacks: The Diamondbacks hope 2B Aaron Hill can return to the starting lineup by midweek. Hill still has a "tweak" in his hamstring, which he pulled Tuesday, manager Chip Hale said.

Cubs: Manager Joe Maddon is not completely ruling out OF/C Kyle Schwarber (rib cage strain) for the series against St. Louis, although he does not anticipate him playing. Schwarber was out of the lineup for the fourth consecutive game. "We'll see what he feels like when he gets to the ballpark tomorrow," Maddon said. "I'm anticipating not being able to use him, but if we are able to use him, that'd be great."

UP NEXT

Diamondbacks: LHP Patrick Corbin (4-3, 3.67 ERA) starts as the Diamondbacks face RHP Mike Leake (9-7, 3.49) and the San Francisco Giants.