Neil Walker hit a two-run homer, Brian Burres limited Atlanta to one run over six innings in his first start in more than three months and the Pittsburgh Pirates beat the slumping Braves 3-1 on Monday.

Despite losing its fourth in five games, Atlanta was assured of remaining in first place in the National League East for at least another day when Florida beat Philadelphia 7-1 in the first game of a day-night doubleheader. The Braves own a one-game lead over the Phillies.

The Braves have led the division every day since May 31, but have lost six games off that edge since July 22.

Atlanta had won five of its previous six against the Pirates, who lead the majors with 91 losses, and likely was looking to this three-game series as a way to get untracked. But the Braves did almost nothing against Burres (3-3), who limited them to David Ross' sacrifice fly in the second during his first start since losing to Atlanta 6-3 on May 29.

Keeping the Braves off balance with an assortment of offspeed pitches mixed in with a fastball that topped out at 90 mph, Burres made his best start since shutting out the Cubs for seven innings on May 6. The left-hander spent much of the season with Triple-A Indianapolis, and started Monday only because Jeff Karstens has arm and shoulder fatigue.

Joel Hanrahan pitched the ninth inning for his fourth save in seven opportunities.

Tommy Hanson (9-11) held the Pirates to an unearned run over five innings. Jose Tabata singled to start the sixth, and Walker followed a drive to straightaway center that made it 3-1. Walker's 10th homer extended his hitting streak to 13 games (22 for 57, .386).

Walker, a late May call-up, has been one the few pleasant surprises during a mostly miserable season in which the Pirates are on pace to lose 108 games. He is hitting .313 as a rookie, has shown good power and has been an above-average fielder despite playing second base for only a handful of games in the minors.

After Burres left, the Braves had their chances against relievers Chris Resop and Evan Meek, but couldn't score while stranding 11 runners overall. The Pirates won despite being limited to four hits by Hanson and relievers Kyle Farnsworth and Peter Moylan.

Resop, claimed on waivers from Atlanta on Aug. 5, walked two to load the bases following Nate McLouth's single, but got Martin Prado to ground out to end the threat. Prado, batting .313, was hitless in five at-bats and is 1 for 17 in PNC Park this season.

Meek, pitching for the first time since being bruised on the right hand by Ryan Braun's line drive Aug. 29 in Milwaukee, retired pinch-hitter Brian McCann and McLouth on grounders in the eighth after the Braves put two on with one out.

Notes: The Braves expect to recall RH relievers Christhian Martinez and Craig Kimbrel from Triple-A Gwinnett on Tuesday. ... Hanson gave up all four Pirates hits. He hasn't won consecutive starts since May 30-June 5, dropping six of seven decisions.