Pinch hitter Dioner Navarro had a game-ending sacrifice fly in the 11th inning, lifting the Cubs to a 4-3 victory over the Pittsburgh Pirates on Sunday at Wrigley Field.
Anthony Rizzo sparked the winning rally with a leadoff single. He advanced on Alfonso Soriano's single and went to third when Pirates catcher Russell Martin threw the ball into center field while trying to pick Rizzo off second.
Luis Valbuena was walked intentionally before Navarro's fly ball to right off Bryan Morris (4-3) gave the Cubs their seventh win in the last 11 games.
Matt Guerrier (3-4) pitched two scoreless innings for his first win with Chicago. He was acquired in the trade that sent Carlos Marmol to the Los Angeles Dodgers on Tuesday.
The Cubs had a 3-2 lead and the Pirates were down to their last strike when Starling Marte drove a 3-2 pitch from closer Kevin Gregg over the wall in center for his ninth homer.
It was Gregg's second blown save in 17 opportunities. He began the inning with consecutive strikeouts against Jordy Mercer and pinch hitter Travis Snider.
Chicago (38-48) improved to 20-18 since it got off to a lackluster start. It has won five of its last seven series.
Pittsburgh (53-34) has dropped three of four to fall into a tie with St. Louis for the NL Central lead and the best record in baseball.
The Cubs grabbed a 3-2 lead when Scott Hairston connected for a pinch-hit solo homer against Tony Watson in the eighth inning. It was Hairston's eighth homer.
Pirates right-hander A. J. Burnett came off the 15-day disabled list after being sidelined by a strained right calf and pitched five solid innings. He allowed two runs, one earned, and three hits.
Cubs starter Carlos Villanueva (2-4) lasted just four innings, by design. Villanueva was making his first start since Scott Feldman was traded to Baltimore, opening a spot in the rotation, and manager Dale Sveum said before the game he likely would keep Villanueva to a 75-pitch count.
Villanueva allowed one run and three hits while throwing 69 pitches. He struck out five and walked one.
Villanueva also helped himself in the third with a broken-bat leadoff single. He moved to third on Starlin Castro's one-out double and scored on an error by first baseman Garrett Jones. Alfonso Soriano's sacrifice fly drove in Castro, who moved to third on Jones' error.
Burnett returned the favor in the fifth. He led off with a single and was erased on a fielder's choice by Marte. But Jose Tabata followed with a double to deep left that tied it at 2.
Tabata also doubled and scored on Andrew McCutchen's double in the fourth.
Pittsburgh threatened in the sixth. Pedro Alvarez led off with an infield single, Martin walked, and the runners moved up on Brandon Inge's sacrifice. Jordy Mercer then hit into a fielder's choice that forced out Alvarez in a rundown between third and home. Pedro Strop then came in and struck out pinch hitter Gaby Sanchez to end the inning.