WASHINGTON -- Ian Desmond singled home Nyjer Morgan in the bottom of the 13th inning and the Washington Nationals overcame Albert Pujols' 400th home run Thursday night in an 11-10 roller-coaster win over the St. Louis Cardinals.

"It's a special milestone," Pujols said of No. 400, "but I don't play for numbers."

Morgan was hit by a pitch from Blake Hawksworth (4-8) while squaring to bunt leading off the inning, then advanced to third on Alberto Gonzalez's one-out single. With the infield in, Desmond bounced a grounder up the middle.

Doug Slaten (4-1) pitched a scoreless inning for the Nationals, who broke out of their offensive doldrums with 16 hits. Washington had been shut out three times in the past week, and the victory ended a four-game losing streak.

The Cardinals scored four in the top of the ninth to take a 10-8 lead, but Roger Bernadina's two-run homer to off Ryan Franklin sent the game to extra innings.

Then, after eight straight innings in which at least one run was scored by one team or the other, the 10th and 11th were barren -- with no hits whatsoever. Willie Harris drew a two-out walk in the 12th, as did Wil Nieves, the last position player available on the Nationals bench. Adam Kennedy hit a blooper up the middle that seemed sure to end the game, but shortstop Brendan Ryan made a diving, snowcone catch to send it to the 13th.

The Nationals used eight pitchers, while the Cardinals used seven in what already had been a busy day at Nationals Park, with Washington introducing this year's No. 1 overall draft pick, Bryce Harper.

Pujols hit his milestone homer leading off the fourth, but it couldn't stop a St. Louis slide that has come at an inopportune time in the playoff race. The Cardinals have lost three straight and eight of 11 -- including a demoralizing two in a row to last-place Pittsburgh before arriving to play last-place Washington.

Pujols sent an 0-1 fastball from Jordan Zimmermann into the right-center seats to become the 47th major league player to reach 400 homers, and the third-youngest to do so. Pujols stood and admired the shot, then was mobbed by teammates when he returned to the dugout.

The slugger also hurt his right ankle in the bottom of the 10th when he tried to plant his foot on the tarp to reach for a foul ball near the first base dugout, but he stayed in the game.