AJ Burnett continued his winning run against the Cincinnati Reds this season as the Pittsburgh Pirates downed the in-form National League Central division pacesetters 6-2.
Burnett, who now has a 3-0 record against Cincinnati this campaign, allowed two runs and three hits in eight 2/3 innings to help the Pirates to victory over a Reds side who had won 15 of their previous 16 games.
The Pirates are now within four 1/2 games of the Reds, with the St Louis Cardinals also taking advantage of the leaders' defeat with a 3-0 win over the Milwaukee Brewers.
Kyle Lohse threw six shutout innings, allowing four hits and fanning six as the Cardinals made it three wins on the trot.
The San Francisco Giants and Los Angeles Dodgers also recorded third straight wins to move further clear of third-placed Arizona Diamondbacks in the NL West division.
The Giants downed the Colorado Rockies 8-3 with Tim Lincecum allowing one run and five hits in six innings and Hunter Pence having three RBIs.
That win sees San Francisco maintain their half-game lead over Los Angeles, who completed a three-game sweep of the Chicago Cubs when Hanley Ramirez's RBI single in the ninth sealed a 7-6 victory.
Arizona fell further adrift after going down 5-4 against the Philadelphia Phillies, with Ryan Howard scoring the winning run in the ninth inning.
It was a good day for teams in the American League East with four of the five sides picking up victories.
Leaders the New York Yankees defeated Seattle Mariners 6-2 with Raul Ibanez scoring a home run and driving in three, while second-placed Baltimore Orioles kept up the pressure with a 1-0 win over divisional rivals the Tampa Bay Rays.
Taylor Teagarden decided the game with an RBI double in the 10th inning - his third hit of the season - while starters Miguel Gonzalez and David Price each allowed just two hits in a low-scoring clash.
Also in the AL East, the Boston Red Sox beat the Minnesota Twins 6-4 while last-placed Toronto Blue Jays won 6-5 at the Oakland Athletics having trailed 4-1 heading into the fourth inning.
Oakland's result completed a clean sweep of losses for the four AL West teams, with the Texas Rangers and the Los Angeles Angels joining the Athletics and Seattle in tasting defeat.
Leaders Texas lost 7-6 against the Kansas City Royals as Jeff Francoeur scored a home run in the fourth inning and helped the winning run cross on a grounder in the 10th.
The Angels were beaten 4-2 by the Chicago White Sox.
Elsewhere, NL East leaders the Washington Nationals made it two wins on the bounce with a 4-1 win over the Miami Marlins, the Atlanta Braves defeated the Houston Astros 6-1, while the Detroit Tigers beat the Cleveland Indians 10-8.