David Freese's hot bat boosted the St Louis's playoff hopes as his five RBIs led the Cardinals to a 6-5 win over the New York Mets on Wednesday.

The win moved St. Louis within 1.5 games of front-running Atlanta in the National League wildcard race after the Braves suffered a 4-0 shutout defeat to Florida.

One and a half (games) is huge because Atlanta is a good team, Freese told reporters after opening the game with a two-run triple before striking a big blow late.

They are not going to fold. Losing is not an option, and we know that.

The Cardinals trailed 4-3 early, but Freese belted a go-ahead three-run homer in the seventh inning and Cardinals reliever Jason Motte shook off a Mets blast in the ninth to close out his team's fourth straight win.

While St. Louis (88-69) tries to claw into contention, Arizona all but settled their post-season plans with an 8-5 win over Pittsburgh, maintaining the Diamondbacks' 5.5-game lead in the NL West with only six more to play.

Second-place San Francisco has little chance of catching Arizona, but they did pull 3.5 games behind the wildcard lead by defeating the Los Angeles Dodgers 8-5.

Despite a 7-1 loss to the Chicago Cubs, the Milwaukee Brewers remain in the box seat with a 4.5-game advantage in the NL Central.

In the American League, the falling Boston Red Sox lost 6-4 to Baltimore, yet still managed to build their lead in the AL Wild Card race thanks to the New York Yankees, who swept their doubleheader with Tampa Bay.

The Rays lost 4-2 in both games to fall 2.5 games behind Boston, level with the Los Angeles Angels, who beat Toronto 7-2.

The Red Sox, meanwhile, have lost 14 of their last 18 games.

We certainly haven't made it very easy for ourselves, Red Sox manager Terry Francona said. That doesn't mean we can't get to where we want to go, but we have our work cut out for us.

The Texas Rangers topped Oakland 3-2 to maintain their five-game lead in the AL West and bring their magic number to three to clinch the division.