WASHINGTON —  Atlanta's Tommy Hanson extended his scoreless innings streak to 26 before Adam Dunn's 300th career homer and the Washington Nationals rallied for four eighth-inning runs and a 5-3 victory over the Braves on Saturday.

Hanson departed with a 3-1 lead after seven innings and was in line for his fifth straight victory before the Braves bullpen blew up, halting Atlanta's winning streak at a season-high five.

Mike Gonzalez (3-1) loaded the bases in the eighth on a pinch-hit single by Ronnie Belliard and a pair of walks before Peter Moylan relieved and yielded a two-run, game-tying single to Ryan Zimmerman.

Eric O'Flaherty replaced Moylan and was greeted by Dunn's decisive single up the middle for a 4-3 lead. Josh Willingham followed with an RBI single to left.

Nationals starter John Lannan was the beneficiary of the rally. The left-hander allowed three runs and nine hits in eight innings, ending Washington's losing streak at four games. Lannan (6-5) walked one and struck out one.

Mike MacDougal worked the ninth for his fourth save, escaping a two-on, one-out jam.

Hanson, who was recalled from Triple-A Gwinnett on June 7 to make his major league debut, took a no-decision in that game and has yet to lose. He allowed only Nick Johnson's single to center in the first and a second-inning infield hit by Anderson Hernandez over the first six innings.

The right-hander walked one and struck out five, lowering his ERA to 2.25 in a 105-pitch effort.

Dunn hit his milestone blast leading off the seventh, crushing a 2-2 fastball deep into the second deck in right field to ruin Hanson's shutout bid. The 29-year-old is the fifth player major league history to reach that total in less than 4,200 at-bats, succeeding in his 4,145th at-bat. The others are Babe Ruth (3,830), Mark McGwire (3,837), Ralph Kiner (3,883) and Harmon Killebrew (3,928).

The Braves took a 1-0 lead in the third on Nate McLouth's RBI single. Brooks Conrad led off with a single to center, moved to second on Hanson's sacrifice bunt and scored when McLouth blooped a single over second base.

In the sixth, McLouth drew a leadoff walk and Martin Prado followed with a double to left before consecutive RBI singles to center by Chipper Jones and Garret Anderson made it 3-0.

NOTES: Lannan has thrown six straight quality starts. ... Atlanta and Washington are tied for the National League lead with nine victories from rookie starting pitchers. ... Washington is 3-2 on July 4 since moving from Montreal before the 2005 season.

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