ST. LOUIS -- As St. Louis thunders down the homestretch to what could be its first National League Central title since 2009, it's doing so with youth leading the way.
Five rookie pitchers took turns shutting down Washington for a third straight game Wednesday as the Cardinals completed a series and season sweep with a 4-1 win at Busch Stadium, reducing their magic number to one.
Shelby Miller (15-9) pitched into the seventh inning, becoming the first St. Louis rookie since Dick Hughes (1967) to reach 15 wins in a season. Seth Maness, Kevin Siegrist, Carlos Martinez and Trevor Rosenthal tag-teamed their way through the last nine outs, with Rosenthal bagging his third save in as many games since replacing struggling closer Edward Mujica.
"They might not have the experience, but these young guys are really doing a nice job," Cardinals manager Mike Matheny said. "It's just a great testament to this organization's draft process and player development."
Another youngster, Matt Adams, doubled and scored in a two-run fourth, then capped the scoring with his 17th homer of the year in the sixth. It was Adams' eighth homer since taking over at first base for the injured Allen Craig three weeks ago.
Rookies pitched the last 19 2/3 innings of this series for St. Louis (94-65), combining to allow six hits and one run. While Miller's outing might not have been as dominant as Michael Wacha's near no-hitter on Tuesday night, it was still effective enough to put the team on celebration's doorstep.
Cincinnati was eliminated earlier Wednesday with a 1-0 loss to the New York Mets and Pittsburgh fell 4-2 at the Chicago Cubs, knocking it three back of the Cardinals with three games left.
"The rookies on the team have done an unbelievable job, and there's a ton of us," Miller said.
Miller survived a shaky first inning in which he issued two walks and allowed a run-scoring single to Bryce Harper. But he found his rhythm from the second inning on, giving up just three more hits and a walk before leaving after missing with a 3-2 pitch to Adam LaRoche to start the seventh.
It was a far cry from his last outing against the Nationals (84-75), when he fanned eight in 6 2/3 innings of a 3-2 win on April 22.
"You're seeing the evolution of a pitcher," Matheny said of Miller. "The last time he faced them, he was pitching up here (pointing at his chest) in the strike zone with his fastball. Now he's pitching more, being more efficient."
"We didn't take advantage of our opportunities," Washington center fielder Denard Span said. "Seemed like every time we'd get a guy on, he'd sink a fastball and get a ground ball. I think it was part him, part us."
Besides edging closer to a division title, the Cardinals also denied Nationals righthander Jordan Zimmerman his 20th win. Zimmerman (19-9) gave up six hits and four runs over seven innings, walking none and whiffing two.
The big hit was Yadier Molina's two-run single in the bottom of the fourth that snapped a 1-1 tie. It scored Matt Holliday, who was hit by a pitch to start the inning, and Adams, who lined a double down the left field line.
From there, St. Louis' fresh-faced fireballers -- every pitcher Wednesday was 24 years old or younger -- locked it down.
"You couldn't picture it any other way," Miller said. "It's been a lot of fun."
NOTES: Holliday (back tightness) returned to the lineup after a three-game absence and batted in the third spot, going 0-for-3 to snap a five-game hitting streak. ... Washington has a day off on Thursday before starting a season-ending three-game series Friday night in Arizona. It will send Stephen Strasburg to the mound against Patrick Corbin. ... The Cardinals also get Thursday off before welcoming the Chicago Cubs to town for their last regular-season series. In Friday night's opener, Lance Lynn will look for his 15th win against Travis Wood.