ATLANTA -- Second baseman Dan Uggla hit a towering three-run homer in the ninth inning against his former team to give the Washington Nationals a dramatic 13-12 win over the Atlanta Braves, and end the team's six-game losing streak.

Uggla, who made the club as a nonroster invitee in the spring, was 3-for-4 with five RBIs against the Braves, the club that released him in June. The homer, his first of the season, came against Braves closer Jason Grilli (0-1), who was trying to earn his eighth save.

The Nationals, who trailed 9-1 after two innings and 10-2 after four innings, completed their biggest comeback win in nearly 12 years.

The winning pitcher was Blake Treinen (1-2), and Drew Storen worked a scoreless ninth inning for his fifth save.

The Nationals, who fell in a big hole when Atlanta scored seven runs in the second inning, kept pecking away. Washington scored four in the fifth, one in the sixth and three in the seventh and trailed 12-10 entering the final inning.

Grilli struck out first baseman Ryan Zimmerman to start the ninth, then allowed a single to catcher Jose Lobaton and walked third baseman Danny Espinosa. Uggla then put the Nationals ahead with a three-run homer.

Lobaton and center fielder Denard Span, who was 4-for-5, also hit home runs for the Nationals.

Atlanta first baseman Freddie Freeman and catcher A.J. Pierzynski each had four hits.

Atlanta ruined the major league debut of Washington's A.J. Cole, who was tagged for nine runs in two innings.

Washington scored a run in the first. Span led off with a single and scored on right fielder Bryce Harper's double down the first-base line.

Atlanta responded with two runs in its half of the first. Right fielder Nick Markakis led off with a single, went to third on a one-out single by Freeman and scored on Pierzynski's sacrifice fly to right.

Third baseman Alberto Callaspo doubled to right to drive in Freeman.

The Braves sent 11 batters to the plate in the second and scored seven times against Cole. The rally included two-run doubles from Simmons and left fielder Kelly Johnson and was prolonged when Cole failed to catch a toss from first baseman Ryan Zimmerman on an grounder that would have ended the inning and instead allowed two runs to score.

Washington got a run back in the third on left fielder Jayson Werth's sacrifice fly that cut the lead to 9-2, only to have Atlanta strike for a run in the fourth on an RBI single by Pierzynski against reliever Tanner Roark.

The Nationals got back in the game by scoring four unearned runs in the fifth. Werth had another sacrifice fly, but the big blow was a three-run homer by Lobaton, his first.

NOTES: Washington optioned RHP Rafael Martin to Triple-A Syracuse to make room for RHP A.J. Cole, who started Tuesday night's game in place of RHP Max Scherzer. Martin (0-0, 9.00) had 11 strikeouts in five innings but allowed a run in his last three appearances. Scherzer (right thumb) threw off the mound on Tuesday and was able to use all his pitches. His next start has not been determined. ... INF Yunel Escobar (left hand) is day to day after being spiked on Monday night. ... Atlanta deviated from its platoon in center field by starting Cameron Maybin rather than Eric Young Jr. Maybin normally starts against left-handers, but the Braves expect to face only one southpaw in the next 10 days. ... Starters for the finale of the three-game series on Wednesday are RHP Jordan Zimmermann (1-2, 5.23 ERA) for Washington vs. LHP Alex Wood (1-0, 3.00) for the Braves. ... The Braves and Nationals meet again for a three-game set on May 8-10 in Washington.