Miguel Montero homered in the bottom of the 10th inning to give Chicago a 3-2 victory over the Milwaukee Brewers on Wednesday night for the Cubs' sixth straight win and 12th in 13 games.
Montero, who allowed a couple wild pitches to get past him in the ninth as the Brewers rallied to tie the score, led off the 10th with a solo blast to left field off Michael Blazek (5-3).
Tommy Hunter (3-2) pitched a scoreless 10th to get the win.
Kris Bryant homered and Anthony Rizzo made a circus catch falling into the stands to lead the keep the Cubs surging.
Ryan Braun went 3 for 4 with a home run for the Brewers.
Chicago had a 2-1 lead entering the ninth inning before Hector Rondon allowed a run to blow his fourth save of the season. After getting into a jam of runners on second and third and none — the result of a base hit, an error and a wild pitch — Rondon appeared on the verge of getting out of it by striking out the next two batters.
But with Jean Segura at the plate, Rondon threw another wild pitch, allowing Braun to score.
In his last appearance on Sunday, Rondon worked out of a bases-loaded jam with none out by striking out the side.
Braun opened the scoring with a long solo shot in the first inning. It was the 250th of his career, moving him just one behind Robin Yount for the most in Brewers history.
The Cubs tied the score in the second as Bryant hit a high drive just into the basket in the right-field bleachers for a solo shot. It was Bryant's 16th on the season.
The Cubs grabbed a 2-1 lead in the fifth inning with a little help from the Milwaukee defense. With Montero on second base and two out, Russell lifted a foul popup into the bullpen area down the right-field line. Both first baseman Adam Lind and second baseman Scooter Gennett went after it. Gennett got there and got a glove on the ball, but it seemed like he was screened by Lind and dropped it.
With new life, Russell singled up the middle off Brewers starter Matt Garza to score Montero.
A few minutes later, the Cubs turned in a spectacular defensive play in almost the same location as Russell's popup.
With one out and a runner on first base, Braun lifted popup into foul territory on the right side. Rizzo raced over, jumped up on the tarp positioned along the wall and then stepped onto the brick wall separating the stands from the field. He appeared to make the catch as he was falling into the stands and first base umpire Mark Carlson initially waved it off.
After Cubs manager Joe Maddon came out, the umpiring got together to discuss the play and then overturned the call, ruling Rizzo made the grab before falling into the stands. The runner on first, Jonathan Lucroy. then was awarded second because Rizzo went into the stands.
Brewers: OF Braun (lower back) returned to the starting lineup. He didn't start Tuesday but pinch-hit in the seventh and flew out to center.
Cubs: INF Tommy La Stella (right oblique) finally is healthy after being sidelined since April. President Theo Epstein said La Stella was sent to the minors to get at-bats and will return by Sept. 1 at the latest.
Brewers: RHP Tyler Cravy (0-3, 5.40) pitches the matinee finale of the four-game series and will be making his first appearance against Chicago.
Cubs: LHP Jon Lester (7-8, 3.22 ERA) is 3-0 with a 1.84 ERA in his last four starts.