PITTSBURGH — Cardinals rookie Dylan Carlson’s three-run homer capped a six-run outburst in the sixth inning against the mistake-prone Pittsburgh Pirates on Friday night, helping lift St. Louis to a 7-2 victory and a doubleheader sweep.

The Cardinals took the opener 6-5 behind home runs from Kolten Wong and Tyler O’Neill and just enough pitching to overcome four errors.

St. Louis, playing its third doubleheader in five days, moved to .500 (24-24) with the win to remain in the mix for a playoff spot.

Andrew Miller (1-1) struck out the side in the top of the sixth to earn the win when the Pirates — playing as the road team on the scoreboard because the game served as a makeup for a postponement earlier in the season due to a COVID-19 outbreak with the Cardinals — self-destructed in the bottom of the inning.

Chad Kuhl (1-3) cruised through five innings but things fell apart in the sixth. Kuhl walked Tommy Edman leading off the inning and Paul Goldschmidt reached on catcher’s interference. Brad Miller then walked on four pitches to load the bases, chasing Kuhl.

Paul DeJong tied it at 2 with a sacrifice fly against reliever Chris Stratton and St. Louis took the lead when Pittsburgh rookie third baseman Ke’Bryan Hayes threw wide of home trying to get Goldschmidt at the plate on a grounder by O’Neill.

Pittsburgh first baseman Josh Bell’s attempt to turn a double-play on a grounder by Matt Carpenter ended up with the ball sailing into left field.

Carlson, called up on Friday for a second stint with the Cardinals, sent Stratton’s offering over the wall in right-center.