ST. LOUIS - Matt Carpenter takes pride in giving St. Louis baseball fans their money's worth.

The Cardinals' third baseman hit a game-ending sacrifice fly in the 11th inning Saturday and the Cardinals once again beat the Pittsburgh Pirates 2-1 in extras.

The Cardinals, who have won five in a row, beat the Pirates 2-1 Friday night on Matt Adams' single in the 10th.

Pittsburgh left a season-high 18 runners on base and the Cardinals stranded just four. St. Louis has won 15 of its last 18 against the Pirates at Busch Stadium.

Thrilling walkoff endings are getting to be the norm for St. Louis, especially against NL Central rival Pittsburgh.

The Cardinals' last three home wins over the Pirates came in walkoff fashion. Five of their last eight wins over Pittsburg ended that way as well.

"Both teams really want to win so bad and you can see it in the way they play," Carpenter said. "It seems like every time we play them, we give the fans free baseball."

It was the case again Saturday as St. Louis got its 14th walkoff win since the start of the 2013 season, and the seventh against the Pirates.

Peter Bourjos doubled to start the St. Louis 11th. He was trapped off second by Jared Hughes (0-1) and caught stealing third. Pete Kozma and Jon Jay singled and Carpenter hit a deep fly to left that easily scored the winning run.

"Every time we play these guys it's like a chess match," Pittsburgh infielder Josh Harrison said. "It always comes down to a big hit, a big play. We just need to get one in our favour every once in a while."

St. Louis manager Mike Matheny was pleased with the way his club took advantage of its limited opportunities.

"I'm really happy about how the guys have been playing. Somebody is always coming up big," Matheny said. "It's fun when you can pull these out like this."

Carlos Villanueva (3-1), the seventh St. Louis pitcher, went one inning. He induced Francisco Cervelli to ground out with two on to end the 11th.

St. Louis starter John Lackey gave up one run and six hits in six innings. He struck out four and walked three.

"My arm felt as good as it has all season," Lackey said.

Pittsburgh started Francisco Liriano was even better. He gave up one run on three hits over eight innings. He did not allow a hit until the sixth.

"The whole key is not to try to do too much and stay calm," Liriano said. "Location-wise everything was (good)."

Harrison hit an RBI single in the third that put Pittsburgh ahead. Gregory Polanco began the inning with a single, stole second and went to third on a throwing error by catcher Yadier Molina.

St. Louis tied it in the sixth on a run-scoring ground out by Jay. Bourjos and pinch-hitter Jason Heyward led off the inning.

"When you play the game every day for six months, you're going to go through some stretches where you get challenged," Pittsburgh manager Clint Hurdle said. "You either meet the demands of the game or you don't. When you don't, you can't really expect (good) results."

TRAINER'S ROOM

Pirates: OF Andrew McCutchen was in the starting lineup after he appeared to hurt his leg while breaking up a double play in the ninth inning Friday night.

UP NEXT

Pirates: RHP Vance Worley (2-2, 4.50) will make his fifth start of the season in the final game of the series on Sunday. The Pirates have been shut out in each of his losses.

Cardinals: RHP Michael Wacha (4-0, 2.42) allowed five hits and one run in each of his first four starts this season. He is 9-1 with a 2.45 ERA in 21 career appearances at home.