The crowd of 40,506 at Busch Stadium had already cheered when the Pirates' loss to the Cubs went final. Minutes later, the Reds fell to the Brewers. When Pete Kozma scored on a passed ball with two outs in the 10th, the Cardinals assumed sole possession of first place.
"Tonight, this is kind of like what postseason games are like," said Matt Carpenter, who dazzled on defense and twice drew key walks. "Sometimes guys can go out and pitch well and games can be won defensively, games can be won on the bases. You see a little bit of everything in the postseason. Tonight's game was similar to that."
What the Cardinals lacked in offense, they made up for with hustle, glove and Yadier Molina's arm. The Mariners provided ample assistance, too. Manager Mike Matheny described it as a night where his club "kind of made something out of nothing."
Having tallied just three hits in Hisashi Iwakuma's seven-inning start, the Cardinals used an error and a botched double-play attempt to tie the game without an eighth-inning hit.
Pinch-hitter Brock Peterson ran hard on a one-out pop up to shallow right field, so when it fell next to rookie second baseman Nick Franklin, he was alertly standing on second.
"It's not too hard to hustle," Peterson said. "I just saw the way the wind was taking the ball and I kind of had a feeling that it might drop."
Kozma ran for Peterson and, after watching reliever Charlie Furbush throw six pitches to Carpenter, decided he would run on the seventh.
"I got a good look," Kozma said. "He was a little slow to the plate."
Kozma slid in safely, which put him in position to score when the Mariners couldn't turn two on Jon Jay's routine grounder to second. Shortstop Brad Miller, another rookie, short-hopped his throw to first.
"We've got a lot of young players up here," Mariners manager Eric Wedge said. "They're very inexperienced. … When you're playing tight ballgames like a lot of our games have been and you're tight late, that's when it really shows itself."
The tie game was preserved by Molina, who helped bail Edward Mujica out of ninth-inning trouble by throwing out two runners trying to steal. It was a feat last accomplished by a Cardinals catcher in 2001, when Matheny was behind the plate.
An inning later, lefty Kevin Siegrist worked around two singles to strand a pair of runners in scoring position. He would soon be rewarded with his third career win.
Reliever Chance Ruffin opened the bottom half of the 10th with two strikeouts before Kozma -- who had stayed in the game to play short -- singled. Carpenter followed with a walk, as did Jay, leaving Oliver Perez to face Matt Holliday with the bases full. His first pitch got away from rookie catcher Mike Zunino, just far enough for Kozma to sprint home from third.
"Pete right there at the end, he has instincts," Matheny said. "He has as good of instincts as we have with anybody on our club as far as baserunning goes."
It was the fourth walk-off win of the season for St. Louis and the first to come on a wild pitch or passed ball since Sept. 24, 2011.
"I was just ready for anything," Kozma said. "You have to do anything you can to get home safely."
While the Mariners' defense was far from crisp, they, in turn, witnessed what Carpenter described as the best defensive performance of his career. Carpenter closed the fifth inning -- which had begun with a 435-foot homer by Zunino -- with the first of his two defensive gems.
Fully extended, Carpenter made a diving stop on a bouncer up the middle to rob Abraham Almonte of a hit. Franklin, who had been on second, rounded third base, anticipating that the ball would get through to the outfield.
Carpenter further caught him off guard by throwing to third. That initiated an inning-closing rundown.
"That was a seeing-eye single … until he came out of nowhere and made that play," Wainwright said. "A huge turn of events there."
Daniel Descalso turned a sixth-inning double play to strand a runner at third. To open the seventh, Carpenter gloved another up-the-middle grounder while diving and threw out Zunino at first.
"To be able to go out and make plays to help us win games is very rewarding," Carpenter said. "I'm just trying to do whatever I can to help us get into the postseason and keep winning."
"I haven't seen a great deal of him other than [on] TV," Wedge added. "But it's obvious he's a heck of a player."
Those plays helped Wainwright navigate through eight innings. The only one of the 114 pitches he wanted back was the high cutter to Zunino, which Wainwright labeled as "probably the worst pitch of my life."
It was the 14th home run served up by Wainwright in 221 2/3 innings pitched.
Though the no-decision precludes Wainwright from having the chance for a 20-win season, he has rebounded from a dismal two-start stretch against the Reds with two strong outings since.
"He's a fighter," Matheny said. "He loves those kinds of games where he can stand up there and show that he's our ace, and he proved it again."