PITTSBURGH -- Francisco Cervelli hit a grand slam and Gerrit Cole pitched seven innings for his 19th win as the Pittsburgh Pirates beat the St. Louis Cardinals 8-2 on Wednesday afternoon in the opener of a day-night doubleheader to keep alive their slim hopes of winning the National League Central.

The Pirates (96-62), who have the second-best record in the major leagues, drew within three games of the Cardinals (99-59) but both teams have just four games remaining.

The Cardinals could clinch their third straight division title in the night portion of the doubleheader.

Both teams have already qualified for the postseason.

Cervelli's second career slam and seventh home run of the season broke a 1-1 tie in the fourth inning, coming off Michael Wacha (17-7). The catcher also doubled and scored on shortstop Jordy Mercer's single in the sixth to make it 7-2.

Cole (19-8) allowed two runs and scattered seven hits while striking out two and walking none. He is 5-0 in his last six starts.

Pirates right fielder Gregory Polanco had two hits and two RBIs while second baseman Neil Walker opened the scoring with a leadoff homer, his 16th, in the second inning.

Cardinals third baseman Matt Carpenter hit his 28th home run to lead off the sixth and draw the Cardinals with 6-2, a 435-foot drive that cleared the right field stands and bounced into the Allegheny River.

Carpenter became the 25th different player to reach the river since PNC Park opened. He also doubled in the fourth and scored on left fielder Matt Holliday's single to pull St. Louis into a 1-1 tie.

Shortstop Jhonny Peralta and catcher Tony Cruz also had two hits for the Cardinals.

Wacha was hammered for six runs in four innings, allowing four hits and four walks while striking out four. It was the right-hander's first loss to the Pirates in five career decisions.

Cardinals right-hander Adam Wainwright, activated from the disabled list prior the game after being out since April 26 with a torn left Achillies' tendon, pitched the eighth inning and gave up a run when third baseman Josh Harrison hit a two-out double and scored on Polanco's single.

It was Wainwright's first relief appearance since the 2006 World Series after making 221 consecutive starts.

Cervelli's slam was set up when center fielder Andrew McCutchen led off the bottom of the fourth with a single and third baseman Aramis Ramirez walked. Both runners moved up on Walker's ground out and Cardinals manager Mike Matheny opted to intentionally walk first baseman Pedro Alvarez to load the bases.

Cervelli followed with a drive into the left field bleacher to put the Pirates ahead 5-1. His other slam came in 2011 when he played for the New York Yankees.

Polanco doubled in a run later in the inning.

NOTES: Cardinals rookie OF/1B Stephen Piscotty rejoined the team Wednesday but was unavailable to play in the doubleheader after sustaining a mild concussion and head contusion on Monday night in a collision with OF Peter Bourjos. Piscotty was hospitalized overnight Monday and rested at the team hotel Tuesday. Doctors are confident Piscotty will be able to play before the regular season ends Sunday. ... Cardinals RHP Adam Wainwright was activated from the 60-day disabled list after being out since April 26 with a torn left Achilles tendon. The longtime ace of the rotation will be used in relief. ... Cardinals RHP Carlos Martinez was placed on the 60-day disabled list to open a spot on the 40-man roster for Wainwright. Martinez left his start Sept. 25 against Milwaukee with a strained right shoulder. ... In the night portion of the doubleheader, Cardinals RHP Tyler Lyons (2-1, 3.96 ERA) will face Pirates RHP Charlie Morton (9-8, 4.54), who has lost nine straight decisions to St. Louis.