""I would not have expected this by any means," said Clint Barmes, the once-and-again starting shortstop whose two-out RBI double in the fourth contributed to erasing Adam Wainwright's early lead. "This is a big series, and we've played a tough series so far. Games have come down to one big moment."
Wednesday's big moment, to the raucous delight of the 31,679 at PNC Park, came in the eighth inning of a game still knotted at 4. Neil Walker stood on second, Trevor Rosenthal stood on the mound and Russell Martin stood in the way of a tie score entering the ninth.
When Martin ripped a 0-1 slider into left-center to easily deliver Walker, the Pirates had their first and lasting lead in the game, and assurance that when the Cardinals depart Pittsburgh following the series finale, they will leave first place in the National League Central behind.
The Pirates assumed a 2 1/2-game lead in the division by climbing a season-high 23 games over .500.
On Thursday night they will go for their first five-game sweep since Sept. 12-15, 1996, in San Francisco.
"They're doing what it takes to win," St. Louis third baseman David Freese said of the Bucs. "They're playing the ball that we wish we were right now. They're obviously having more fun than we are right now. They're capitalizing on both sides of the ball when they need to, and we're just not doing it."
This is capitalizing: Walker had begun the eighth with a single, then tagged up and went to second as Pedro Alvarez flied out into the left-field corner for the second out.
"We see it all the time," Walker said of deep drives into PNC Park's vast left field, "and if you can read the ball off the bat well enough, you try to take advantage of the situation."
Manager Clint Hurdle calls those extra bases of opportunity "free 90s."
"That's one of the advantages we can use in this park, because we can do that better than anybody else," Hurdle said, citing his players' familiarity with their home field. "It's good baseball play. You get yourself in scoring position, get a sharp single, you go up -- and [Mark] Melancon comes in."
Tony Watson earned the victory after blanking St. Louis for two innings as the second man out of the bullpen in support of a shaky Jeff Locke, and Melancon handled the ninth for his sixth save.
On a night when young lefty Locke was not at his frugal best, the Pirates lived by their one-more-run-than-them credo.
"This is the most on and off we've seen Jeff," Hurdle said. "He was pitching to the edges, not getting back into counts, after throwing 17 first-pitch strikes out of 23. But he gave it everything he had. But after four runs and 10 hits, it was time to pull the plug."
The Cardinals figured out the combination for Locke. They got to him for more hits in the first inning -- four -- than the lefty had allowed in 10 of his first 20 starts. Two of the singles, by Matt Holliday and Daniel Descalso, drove in runs, and the hits kept coming, many of them weak dribblers, but they all counted.
By the end of the fourth, which was also the end of his night, Locke had surrendered 10 hits, more than in any of his prior 30 career starts. But he also departed with the Pirates trailing by only a run, a testament both to his own ability to wiggle out of jams and to his mates' ability to respond.
"Sure I was frustrated when I left," said Locke, whose ERA crept up, from 2.15 to 2.36, "because you'd like to give the team a better effort. But I wasn't in here crying about it, saying, 'We're not going to win tonight because I didn't do good.'
"I know for a fact these guys fight for nine, and that's what we did, and that's why we won."
The Bucs would not let Adam Wainwright get away with any shutdown innings, the most convincing shifters of momentum in any game.
Alvarez's two-out RBI single answered in the bottom of the first.
After St. Louis eked out a third-inning run on Tony Cruz's groundout with runners at the corners and one out, Walker replied in the bottom with a shot into the right-field seats, his first home run since June 26.
The Cardinals once again moved two runs up in the fourth, with Holliday singling for a run. In the bottom of the frame, Barmes snaked a two-out opposite-field double off the box-seat railing to deliver Alex Presley from first base.
The give-and-take ended in the fifth. Vin Mazzaro didn't give the Cardinals anything, and Andrew McCutchen's sacrifice fly took away Wainwright's last lead, tying the score at 4.
"I'm just real frustrated that the offense does a great job going out there against an All-Star pitcher," Wainwright said, "and scores four runs, gets 10 hits and gets him out of there early. They gave me the lead three times, and I just blew it three times."