PITTSBURGH — By winning three of four games in Pittsburgh, the Chicago Cubs made a bold move as they try to catch the Pirates for the top NL wild card.
Manager Joe Maddon wants more.
Anthony Rizzo started a six-run fifth inning with his 30th homer, and the Cubs rallied for a 9-6 victory Thursday.
Chicago pulled within two games of the wild-card leaders. Should the teams end up tied at the end of the regular season, Chicago would have home-field advantage, having won the season series with 10 wins in 16 games.
Pittsburgh began the day four games behind first-place St. Louis in the NL Central. The Cardinals were set to play a night game at Milwaukee before going to Chicago for the start of a three-game series Friday against the Cubs.
"The division title is still the goal," Maddon said. "That's what we're after."
The Cubs turned a 4-3 deficit into a 9-4 lead with a fifth-inning outburst that included a two-run double by reliever Clayton Richard (4-2) and RBI singles by Addison Russell and Tommy La Stella.
Cubs rookie Kris Bryant had his second straight three-hit game. La Stella and Russell drove in two runs each and were two of four Chicago players with two hits, along with Rizzo and Dexter Fowler.
"The whole group was outstanding in this series," Maddon said. "A lot of good stuff going on out there with a lot of guys picking each other up."
Richard allowed two runs in 3 1-3 innings in relief of starter Kyle Hendricks, who gave up four runs on three homers in three innings. Travis Wood struck out five in two perfect innings for his second save.
Richard began the season with the Pirates' Triple-A Indianapolis farm club before the Cubs purchased his contract July 3.
"It was a little weird facing those guys, but you can't really think about that when you're on the mound," Richard said. "I'm just happy the Cubs gave me an opportunity and I'm enjoying it."
Charlie Morton (9-8) lost for the fourth time in five starts as he was rocked for six runs — five earned — and nine hits in four-plus innings.
Gregory Polanco and Pedro Alvarez both homered while finishing with two hits and two RBIs for the Pirates. Travis Snider also went deep, and Neil Walker and Jordy Mercer had two hits each.
Polanco hit an RBI single in the seventh and scored on Walker's double to pull the Pirates to 9-6, but they got no closer.
"We played hard. We didn't play well enough and we didn't play good enough baseball, and that's the focus point," Pittsburgh manager Clint Hurdle said of losing the series. "We've got to play better baseball moving forward."
The Pirates went ahead 4-3 in the third when Polanco led off with his ninth home run and Alvarez hit a two-run shot, his 24th.
The Cubs built an early 3-0 lead. They scored in the first inning on a double-play grounder and then Russell and La Stella had RBI doubles in the second.
Snider hit a solo homer in the second, his fourth of the season and first since the Pirates re-signed him last month after he was released by Baltimore.
Cubs: RF Jorge Soler was activated from the 15-day disabled list after being out since Aug. 24 with a strained left oblique. He did not play.
Pirates: Mercer replaced SS Jung Ho Kang in the top of the first inning after the rookie sustained a season-ending injury to his left leg when Chris Coghlan slid into him while unsuccessfully attempting to break up a double play.
The team said late Thursday night that Kang underwent surgery to repair a fractured tibia and a torn meniscus. The 28-year-old Korean is expected to be out six to eight months.
Kang called it "a serious injury" in a statement released through agent Alan Nero, but did not blame Coghlan. "Coghlan was playing the game the way it should be played," Kang said. "I'm confident he meant me no harm. I appreciate everyone's support."
Cubs: Chicago opens a three-game series and 10-game homestand Friday against St. Louis. RHP Dan Haren (9-9, 3.87 ERA) starts against Cardinals RHP Lance Lynn (11-10, 3.17).
Pirates: Pittsburgh begins a three-game series and 11-game road trip Friday night at Los Angeles with LHP Jeff Locke (8-10, 4.43) facing Dodgers RHP Zack Greinke (17-3, 1.61), the major league ERA leader.
AP Sports Writer Will Graves contributed to this report.