ST. LOUIS -- Peter Bourjos had no trouble calling the 310th hit in his big league career the biggest.
"I had a walkoff hit in Anaheim, but I think at this point, we're leading the division and it's a big game in September and the one in Anaheim was in August," Bourjos said. "So this is the biggest hit."
Yadier Molina walked with two outs in the ninth on a 3-2 pitch from Mark Melancon (2-4), who had entered an inning earlier. It was the first time Melancon's pitched more than one inning since Oct. 2, 2012.
Molina advanced to second on John Jay's single and scored on the hit by Bourjos, easily beating the throw home from center fielder Andrew McCutchen.
"I was just hoping that Yadi was able to score," Bourjos said. "I wasn't too sure with McCutchen playing out there. I didn't know if he was playing shallow or deep, and I watched the play develop, and luckily Yadi was able to beat the play."
Molina saw third base coach Jose Qquendo waving an arm to send him.
"I was thinking home plate all the way," Molina said. "No one was going to stop me there."
"Two outs in that situation and we're in a tight game, his value to me being behind the plate outweighs what we're going to get on the bases from someone," Matheny said. "If he gets thrown out, it's a different conversation right now. He's done such a great job in big games, we need him out there."
St. Louis moved into sole possession of the NL Central lead for the first time Monday and extended its lead to 2 1/2 games with a three-game sweep that dropped the Pirates five games back. Pittsburgh has lost 10 of its last 12 road games, falling to a major league-worst 17-29 away from home in day games.
"They were just a little bit better than us every game," Pittsburgh manager Clint Hurdle said. "I mean, we're playing competitive baseball. We've got to find a way to score a run every now and then when we're out there and have some shutdown innings. We're not going to back down. We'll take the day off. We're going to catch our breath and try and set some stakes down in Chicago."
Trevor Rosenthal (2-6) pitched a one-hit ninth, aided by the eighth double play he's induced this season. Both of his wins have come against the Pirates on ninth-inning walkoffs.
Plate home umpire Ron Kulpa issued a warning to both benches in the fifth inning after Miller threw a high fastball that sailed behind McCutchen. In the fourth, Volquez had hit Matt Holliday and Matt Adams back to back.
Hurdle was not pleased.
"This guy has been hitting it in a teacup all day and he's not near anybody all day," Hurdle said of Miller. "Then you fire that pitch. If he hits him, maybe you toss him. He (Kupla) was there in Arizona when McCutchen got hit.
"He (Volquez) hits him (Adams) in the foot when it's 0-2. He's not trying to hit him. He's not trying to hit Holliday when it was 0-2 and runs it to 2-2. From my perspective, it was an ambush. It was a cheap shot. Ron's got to make the call he makes and that's what he chose to make."
NOT RUNNING WILD
Pittsburgh catcher Russell Martin threw out Jay attempting to steal third in the eighth. Martin has thrown out runners attempting to steal in four straight games and leads the NL with 25 runners caught stealing -- four short of his league-high total last year.
Pirates: Infielder Pedro Alverez (left foot) sat out for the seventh consecutive game. Alverez left the Aug. 26 game against St. Louis in the seventh inning when he hurt the foot diving for a grounder down the first-base line.
Cardinals: Kolten Wong was back in the starting lineup at second base after a two-day absence.
Cardinals: RHP Michael Wacha (5-3, 2.79) starts Thursday at Milwaukee in his first big league appearance since June 17. Wacha missed 67 games because of a stress reaction in his right shoulder. He allowed one hit during two scoreless innings Sunday in an injury rehabilitation outing at Tulsa of the Double-A Texas League.