Anthony Rizzo smacked two homers, including the go-ahead grand slam in the bottom of the sixth inning, as the Chicago Cubs downed the Pittsburgh Pirates, 13-9, in the rubber match of a three-game set.
With the bases loaded and none away in the sixth, Jared Hughes (2-2) relieved Rick van den Hurk and allowed an RBI single to Barney. Rizzo stepped up next and pulverized a grand slam deep into the right-center field bleachers for a 10-9 Cubs lead.
"He's been spectacular," Cubs manager Dale Sveum said of Rizzo, who upped his average to .300 with three hits.
Rizzo drove in six and scored three runs, Alfonso Soriano tallied three hits, two RBI and a run scored, Joe Mather hit a solo shot and Darwin Barney recorded two hits, scored three runs and drove in an RBI for Chicago, which has won seven of its last nine games.
Jeff Beliveau (1-0) picked up the final two outs in the visitors sixth for the win.
Pedro Alvarez cracked a pair of homers and racked up five RBI for the Pirates, who have dropped eight of their last nine contests and sit three games behind the Cardinals for the last NL wild card spot.
"It's tough to lose. ... We just have to keep grinding," Alvarez said.
The Cubs tacked on three runs in the eighth when Soriano belted an RBI double and David DeJesus added a two-run single, which made it 13-9.
Earlier, Chicago struck first in the opening frame when Soriano hit an RBI single to center field, but Pittsburgh tallied six unanswered runs.
Rod Barajas smacked a two-run shot and Andrew McCutchen slapped an RBI single in the second, while Alvarez stroked a two-run blast and Starling Marte added a run-scoring single in the fifth for a 6-1 Pirates spread.
Chicago, though, pushed across four in the bottom half to get back in the game.
Mather hit a one-out solo blast over the wall in left field, Rizzo clubbed a two-run shot into the center-field seats and Wellington Castillo added an RBI single later in the frame and cut the deficit to 6-5.
Pittsburgh scored three runs in the sixth on an Alvarez three-run homer into left-center field, which gave the Pirates a 9-5 lead.
The Cubs were 6-for-10 with runners in scoring position and left seven men on base, while Pittsburgh finished 3-for-10 with RISP and stranded 10 ... Alvarez has 29 homers on the year ... Soriano has 101 RBI on the season.