"The pitch that is just absolutely going to cost me some sleep tonight." -- Garrett Mock, on the 3-2 pitch that Albert Pujols lined to center for the game-winning RBI.

THE RESULT: Albert Pujols hit a go-ahead single in the sixth inning, making a winner out of Adam Wainright for the 16th time this season, as Garrett Mock and the Washington Nationals fell to the St. Louis Cardinals, 2-1, completing a three-game sweep, before 41,083 at new Busch Stadium.

Mock (L, 3-6, 5.01) was excellent, as he gave up just two earned runs on four hits and one walk over six innings, striking out five. Tyler Clippard, Sean Burnett and Mike MacDougal kept the Cardinals off the scoreboard as well.

But Wainwright (W, 16-7, 2.47) was a little bit better. He allowed one earned run on three hits and three walks, striking out seven. Three relievers threw one-hit ball for three innings to shut down any chance of the Nats tying the game.

After the game, the Nationals traded 2B Ronnie Belliard to the Los Angeles Dodgers for minor league pitcher Luis Garcia and a player to be named later, expected to be another minor league pitcher. The team then recalled OF Justin Maxwell from Triple-A Syracuse to replace Belliard on the active roster.

Garcia, 22, is a right handed reliever, and was 5-3 with five saves for the Dodgers Single-A affiliate, with a 2.92 ERA and 3.67 K/BB rate in 2009. In 78 career minor league games over four season, Garcia is 13-4 with a 3.21 ERA and 1.353 WHIP.

THE TAKEAWAY: Mock is turning into a pitcher before our very eyes. In his last six starts, he's given up more than two earned runs just once. He's struck out five or more in each of his last five starts.

He is 3-2 in August and his ERA for the month is 3.31 with 33 strikeouts in 32.2 IP.

THE GOOD: Mock. A sac fly and hit-and-run were the only plays that resulted in runs scored for the slugging Cardinals.

THE BAD: Whoa, where was the offense? Wainwright is having a tremendous season, and he completely dominated the Nats on Sunday.

THE UGLY: The loss drops the Nats road record to 19-46, and 14-21 in one-run games.

NEXT GAME: Washington (46-85) ventures to San Diego (56-76) for a three-game set with the Padres. Livan Hernandez (7-8, 5.36) makes his second start for the Nats since being picked up as a free agent against Tim Stuffer (2-6, 4.11) at 10:05 pm ET.