Updated

Mistakes by a few of the Seattle Mariners rookies cost them dearly. On-the-job training can be like that sometimes.

Nick Franklin got caught in a rundown and dropped a pop fly at second base for a two-base error that led to the tying run in a 2-1, 10-inning loss to the St. Louis Cardinals on Friday night. The winning run scored when the ball popped out of catcher Mike Zunino's mitt for a passed ball.

"We've got a lot of young players up here," Seattle manager Eric Wedge said. "When you're playing tight ballgames like a lot of our games and you're tight late, that's when it really shows. Whether it be defense, at home plate or on the mound, that's what we've seen a lot of."

Pete Kozma scored the deciding run and the Cardinals regained the NL Central lead by a game after Pittsburgh lost. St. Louis is 6-1 on a nine-game homestand.

Kozma entered in the eighth inning as a pinch runner, later stole third base and scored the tying run.

In the 10th, Kozma singled with two outs off Chase Ruffin (0-2). Oliver Perez walked Matt Carpenter and Jon Jay to load the bases.

Zunino couldn't handle the first pitch to Matt Holliday, with the ball rolling free and Kozma scoring on a head-first slide.

"I just sort of lost track of it heading toward my glove," Zunino said. "It's frustrating, especially when I take a lot of pride."

Franklin, the second baseman, dropped pinch-hitter Brock Peterson's towering pop fly in the eighth for a two-base error that helped the Cardinals tie it. Kozma stole third on Carpenter's full-count walk, then scored on Jay's grounder off Charlie Furbush.

"It got up in the air and the ball started traveling on me," Franklin said. "When it started traveling on me, I had to go get it and I fell short of it."

Franklin went to third on Abraham Almonte's two-out infield hit in the fifth and thought he'd score but Carpenter fielded the ball on the outfield grass and Franklin lost his footing rounding third.

"Originally they sent me to go and then I put on the brakes, and as soon as I put on the brakes I kind of slipped," Franklin said. "So I had a little bit a tough time."

Rookie Kevin Siegrist (3-1) worked around two hits in the 10th for the win. He has not allowed a run in 19 1-3 innings.

Zunino homered for the Mariners, who have lost a franchise-record 13 games in extra innings, including their last six in a row.

The Cardinals have won their last four extra-inning games. Gold Glove catcher Yadier Molina helped them get there this time, throwing out pinch-runner Endy Chavez and Dustin Ackley when they tried to steal in the ninth.

Hisashi Iwakuma allowed three hits in seven scoreless innings for Seattle.

Adam Wainwright allowed a run in eight innings. The 16-game winner was hurt only by Zunino's 435-foot homer in the fifth.

The Cardinals struggled against Milwaukee pitching the previous series, with Wily Peralta and Marco Estrada both carrying no-hit bids into the sixth. St. Louis also struggled against Iwakuma, and one of the biggest cheers came when the final score was posted for the Pirates' 5-4 loss to the Cubs.

Zunino had been 4 for 30 in 10 games since coming off the 15-day disabled list from a broken left hand that sidelined him more than a month. He connected for his third homer of the season and first since July 22.

NOTES: Iwakuma topped 200 innings for the season in the fourth. ... It was 70 degrees at game time, a 25-degree drop from two days earlier. ... 2B Carpenter hit his major league-leading 49th double in the third and made the defensive play of the game in the seventh with a sliding stab in the outfield grass and throw to rob Zunino of a hit. ... A pair of rookies get the call on Saturday night, with Michael Wacha (3-0, 2.72) making his seventh career start for the Cardinals and James Paxton (1-0, 1.50) making his second career start for Seattle. ... Former Cardinals 3B Ken Oberkfell threw the ceremonial first pitch. ... Kyle Seager started his 100th consecutive game at 3B, extending his Mariners' franchise record. ... Mariners radio rookie play-by-play man Aaron Goldsmith called a game in his hometown for the first time.