Pettibone (2-0) allowed one run and five hits in 6 1-3 innings in his third start filling in for injured lefty John Lannan.
Donovan Solano hit a solo homer for the Marlins, who've lost three in a row after winning three straight.
Ricky Nolasco (2-3) gave up four runs and eight hits in six innings.
PIRATES 3, NATIONALS 1
Burnett (3-2) gave up five hits and one walk in winning his third straight after going 0-2 in his first three starts. He also raised his NL-leading strikeout total to 57.
Mercer's two-run home run off Ross Detwiler (1-3) in the fifth inning put the Pirates ahead 3-1. Mercer was recalled from Triple-A Indianapolis before the game when second baseman Neil Walker was placed on the disabled list with a right hand injury.
The Nationals lost for the fourth time in six games.
METS 7, BRAVES 5, 10 INNINGS
The Mets, who have won two in a row after dropping six straight, scored four of their first five runs on homers before taking a two-run lead off Jordan Walden (1-1) in the 10th. Walden gave up two runs while getting just two outs.
Jeurys Familia earned his first save by retiring facing the minimum in the bottom half of the 10th.
Closer Bobby Parnell (2-0) got two outs for the win.
CARDINALS 6, BREWERS 1
Miller (4-2) gave up seven hits and a walk in six innings while striking out five.
He held Milwaukee scoreless through the first five innings before allowing a sacrifice fly by Jonathan Lucroy. Carlos Martinez, Seth Maness and Fernando Salas held the Brewers without a run over the final three innings. Martinez and Maness made their major league debuts.
The Cardinals jumped in front in the third inning on a two-out, two-run home run by Holliday off Brewers starter Kyle Lohse (1-3). Allen Craig followed with a single but was thrown out at the plate attempting to score on a double by Yadier Molina, one of three Cardinals thrown out at the plate.
REDS 6, CUBS 5
Mike Leake (2-1) gave up two runs and nine hits in 5 2-3 innings, earned his fourth straight decision over the Cubs with help from five relievers.
RAYS 7, ROCKIES 4, 10 INNINGS
DENVER -- Evan Longoria hit a tiebreaking single in the 10th inning and Kelly Johnson later added a two-run homer in the interleague game, helping Tampa Bay improve to 3-4 on their road trip after having a game in Kansas City snowed out the day before.
Desmond Jennings also had a two-run homer for the Rays.
Ben Zobrist led off the 10th with a double to left off reliever Matt Belisle (1-2), setting the stage for Longoria. Johnson provided some insurance by lining his fourth homer of the season just over the wall in right-center.
Copyright 2013 by The Associated Press
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