PITTSBURGH -- With two months remaining in the season it is too early to say the balance of power has shifted in the National League Central.
However, the Pittsburgh Pirates have shown through the first three games of their five-game series that they are a serious threat to the St. Louis Cardinals.
Rookie Brandon Cumpton pitched seven scoreless innings for his first major-league victory and Andrew McCutchen hit a two-run home run to spark the Pirates to a 6-0 victory over the Cardinals in the second game Tuesday night and a sweep of a doubleheader at PNC Park.
The Pirates won the first game 2-1 on Alex Presley's RBI single in the bottom of the 11th inning.
The Pirates moved to the top of the NL Central standings, 1 1/2 games ahead of the Cardinals, by winning the first three games of the five-game set.
Cumpton (1-1) allowed just three hits in his fourth career start, walking one and striking out five. He retired the last nine batters he faced.
Jeanmar Gomez pitched two innings to complete the three-hit shutout.
The Pirates, who haven't had a winning season since 1992, won for the fourth time in five games to move 22 games over .500 at 64-42.
McCutchen was one of four Pirates with two hits along with Jordy Mercer, Gaby Sanchez and Josh Harrison.
St. Louis rookie left-hander Tyler Lyons (2-4) gave up four runs -- three earned -- and eight hits in six innings with one walk and five strikeouts.
Cardinals All-Star catcher Yadier Molina left the game after the third inning with a strained right knee.
In the nightcap, the Pirates scored the game's first run in the second inning thanks to poor defense by the Cardinals. Jose Tabata reached on third baseman David Freese's fielding error with one out and eventually scored on Molina's passed ball.
The Pirates then made it 4-0 with a three-run fifth as Starling Marte scored on Mercer's single and then McCutchen hit a two-run home run, his 15th, that bounced off left fielder Matt Holliday's glove and over the fence.
The Pirates scored twice more in the seventh on an RBI double by Gaby Sanchez and a sacrifice fly by Tony Sanchez.
In the opener, Russell Martin and pinch-hitter Gaby Sanchez drew back-to-back walks from Kevin Siegrist (0-1) with one out in the 11th. Presley, who was recalled from Triple-A Indianapolis on Monday, then hit a bouncer that deflected off Siegrist's glove and into center field, enabling Martin to score.
Vin Mazzaro (6-3) pitched one scoreless inning for the win. Presley had two of Pittsburgh's six hits.
Both starting pitchers were outstanding, though they didn't factor in the decision.
Pittsburgh's A.J. Burnett allowed one run and three hits in seven innings with three walks and nine strikeouts. St. Louis' Lance Lynn gave up one run and three hits in six innings while striking out seven and walking two.
Holliday had two of the Cardinals' six hits.
St. Louis center fielder Jon Jay's errorless games streak ended at 245, a club record for a Cardinals outfielder, in the fifth inning when he bobbled a single by Marte, allowing him to take an extra base.
NOTES: The Cardinals recalled RHP Michael Blazek and RHP Keith Butler from Memphis to give them fresh bullpen arms for the doubleheader. LHP Marc Rzepczynski and RHP Fernando Sales were optioned to Memphis. Rzepczynski was later traded to the Cleveland Indians for minor-league INF Juan Herrera. ... Slumping St. Louis 1B Allen Craig did not start either game. He struck out as a pinch-hitter in the first game, making him 0-for-18 with 10 strikeouts in his last six games. ... Pittsburgh C Tony Sanchez saw his first action behind the plate when he started the second game. Sanchez made his major-league debut last month by serving as the designated hitter in two interleague road games. ... A pair of All-Stars square off Wednesday night as Cardinals RHP Adam Wainwright (13-6, 2.51) faces Pirates LHP Jeff Locke (9-3, 2.15).