Late home runs by Albert Pujols and Yadier Molina rallied the St. Louis Cardinals only to see them fall short yet again.

Reliever Fernando Salas gave up a three-run homer to Danny Espinosa in the bottom of the 10th inning to give the Washington Nationals a 7-4 win Thursday night. It was the sixth straight loss for the Cardinals, who were swept in consecutive series at Milwaukee and Washington.

St. Louis trailed 4-2 going into the eighth and forced extra innings against the Nationals' top two relievers.

"The effort today was outstanding," St. Louis manager Tony La Russa said. "To come back the way we did, in the last game of a road trip, it makes it a tougher loss."

The Cardinals remain one game behind Milwaukee for the lead in the NL Central. The current losing streak is their longest since Sept. 10-17, 2008 — when they dropped seven straight.

"It's pretty frustrating, but there's nothing you can do," Pujols said. "We're trying our best out there."

Pujols hit his 16th homer of the season off Tyler Clippard with two outs in the eighth. Molina led off the ninth with his fourth home run off closer Drew Storen, who blew his second save in 18 chances.

Matt Holliday, back in the lineup after missing 13 games with a left quadriceps injury, led off the second inning with his seventh homer in his first at-bat.

"I felt pretty good about my swing coming into the game," Holliday said. "You never know going against live pitching, but I saw the ball pretty well."

After sending the game to extra innings, St. Louis had the heart of its order at the plate in the top of the 10th. Sean Burnett (2-3), Washington's fourth pitcher, pitched a scoreless inning, finishing it by striking out Lance Berkman looking.

In the bottom of the 10th, Salas (3-1) returned to the mound for his second inning of work. Ryan Zimmerman led off with a single, and with one out, Salas hit Michael Morse with a pitch. Espinosa followed by hitting a 2-1 changeup into the bullpen in right. It was his 12th home run of the season, and the first allowed by Salas.

"He wasn't the same pitcher in the second inning," La Russa said.

The Nationals, who have won six straight for the first time since they closed the 2009 season with seven in a row, tagged starter Kyle Lohse for three home runs. In his first 91 innings this season, Lohse allowed five.

Washington began the first inning with back-to-back home runs from Jayson Werth and Roger Bernadina. After Holliday's homer made it 2-1, St. Louis tied it at 2 in the fourth when Molina's infield out scored Pujols.

Laynce Nix led off the bottom of the sixth with his 10th home run to give the Nationals a 4-2 lead.

Lohse allowed four runs and seven hits in six innings. He walked one and struck out three.

The Cardinals head back to St. Louis for a nine-game homestand starting against Kansas City on Friday.

"You just try to turn the page and move on to tomorrow," Holliday said. "We have a nice homestand which we haven't had this far into the season, so we need to go home and win some games."

NOTES: Pujols made an error at third base in the ninth inning. He had been moved there from first an inning earlier. It was the third error he committed at third in the last two games. ... To make room for Holliday, the Cardinals placed RHP Eduardo Sanchez on the DL with a strained right shoulder. St. Louis has used the DL 13 times this season — the same number as all of 2010. ... Nationals OF Rick Ankiel missed his second straight game because of a strained intercostal muscle. ... Tyler Greene started at SS for St. Louis for the first time since May 25. Ryan Theriot was rested. ... It was La Russa's 2,499th game as manager of the Cardinals.