ST. LOUIS -- The opener of a three-game National League Central showdown turned into a slugfest.
Breaking it open with seven runs in the bottom of the seventh inning, St. Louis drew within a half-game of first-place Pittsburgh with a 12-8 verdict on Friday night at Busch Stadium.
Joe Kelly (8-3) scattered eight hits over six innings to win his eighth straight decision dating to July 12. It was his third win in just over a month against the Pirates, who have won 10 of the teams' 17 meetings this year.
A.J. Burnett (7-10) lasted only three innings in his shortest start of the year, allowing six hits and five runs. Burnett was 3-0 with a 2.59 ERA in five previous outings this season against the Cardinals.
The first nine St. Louis batters collected hits in the seventh, with Yadier Molina capping the scoring with a three-run homer over the Cardinals' bullpen in left-center field after being brushed back with the first pitch from reliever Bryan Morris.
Warnings were issued by plate umpire Tony Randazzo after that pitch. Randazzo then ejected St. Louis reliever John Axford and manager Mike Matheny during a four-run Pittsburgh eighth when Axford drilled pinch-hitter Tony Sanchez with a 96 mph fastball.
The Pirates added three in the ninth, forcing the Cardinals to wave in closer Edward Mujica from the bullpen. He got the last out for his 36th save.
The Cardinals (81-60) banged out 16 hits, with Jon Jay and Carlos Beltran picking up three each, as they won for just the third time in nine games. The Pirates (81-59) lost their second straight game and remain a victory shy of their first winning season since 1992.
St. Louis reached Burnett for two runs in the bottom of the first. Beltran lined a single to center, scoring Matt Carpenter, and Andrew McCutchen let the ball skip past him for an error that sent Jay home.
The Cardinals pounded out four straight extra-base hits to open the third, expanding the lead to 5-0. Carpenter tripled into the right field corner, followed by consecutive doubles from Jay, Matt Holliday and Beltran.
The Pirates got on the board in the fifth on Pedro Alvarez's two-out RBI single, but that was it for their offense despite numerous scoring opportunities. They left the bases loaded in the first and stranded two in the second, fourth and fifth.
NOTES: St. Louis Friday activated RHP Jake Westbrook (lower back strain) from the 15-day disabled list. Westbrook is 7-8 with a 4.49 ERA in 19 games this year, 18 of them starts, but hasn't won since July 24. ... Pittsburgh will start LHP Jeff Locke in Saturday night's game against Cardinals RHP Adam Wainwright. Locke was briefly demoted to Double-A Altoona on Aug. 28 because of his struggles since the All-Star break. He's 1-2, 6.18 in eight starts and hasn't won since July 21 in Cincinnati. ... Pirates LHP Wandy Rodriguez, who has been on the disabled list since June 11 with forearm tightness, made his first rehab start on Friday night in the International League playoffs for Indianapolis (Triple-A). Rodriguez pitched three innings, allowing three hits and two runs -- one earned -- with a strikeout.