Pete Kozma drove in the go-ahead runs in the top of the ninth as visiting St. Louis battled back from a six-run deficit to stun Washington and advance to the National League Championship Series.

Trailing 7-5, the Cardinals loaded the bases against Drew Storen (1-1) in the ninth on a double by Carlos Beltran and back-to-back two-out walks. Daniel Descalso came up next and ripped a sharp grounder to the left of second base that glanced off shortstop Ian Desmond's glove and into center field to plate two runs.

Kozma followed and slapped a single down the line in right to score David Freese and Descalso with the go-ahead runs. Jason Motte (1-0) allowed a run in the eighth but worked a 1-2-3 ninth to close it out.

Descalso went 3-for-5 with three runs scored and three RBIs and Matt Holliday drove in a pair for the Cardinals, who improved to 6-0 in elimination games over the last two postseasons.

Jayson Werth, whose walk-off homer in Game 4 evened the series at 2-2, picked up right where he left off with a leadoff double in the first. Bryce Harper followed with a triple off the wall in center field and Ryan Zimmerman capped the three-run frame by belting a 1-0 cutter from Adam Wainwright (0-1) into the front row in right-center.

Wainwright almost let it get out of hand in the third, as Harper led off with a deep solo home run to right-center. Zimmerman reached with a double and Michael Morse ended Wainwright's night two batters later with a line drive into the bullpen in left-center for a 6-0 edge.

But St. Louis chipped away, getting on the board with Holliday's RBI double in the fourth and adding two more runs in the fifth when Nationals starter Gio Gonzalez struggled with his command. Holliday's RBI groundout in the seventh cut it to 6-4 and Descalso sent a solo home run down the line in right in the eighth.

GAME NOTEBOOK: The Cardinals will open the NLCS against the host San Francisco Giants Sunday. ... The Washington/Montreal franchise was on the verge of its first ever postseason series win. The 1981 Montreal Expos were the last team to reach the playoffs and fell to the Los Angeles Dodgers in the NLCS. A Washington-based franchise has not won a playoff series since the Senators took the World Series in 1924. ... St. Louis is bidding to become the first team to repeat as World Series champions since the New York Yankees took three straight from 1998-2000.