Alex Rodriguez clubbed the 23rd grand slam of his career - matching Lou Gehrig's MLB record - to steal a 6-4 win for the New York Yankees against the Atlanta Braves.
The American League East leaders were down 4-0 in the top of the eighth when Rodriguez wiped out the deficit in an instant.
Nick Swisher then put the Yankees ahead soon after as his side wrapped up their fifth win in a row.
The Los Angeles Dodgers became the first side in the MLB to hit 40 wins for the season as they beat city rivals the LA Angels 5-2, ending a four-game winning streak.
Four runs off starter Jerome Williams in the bottom of the eighth sealed it, with Juan Rivera's three-run homer doing the bulk of the damage.
National League East leaders the Washington Nationals stretched their own winning streak to five matches with a 4-2 victory over the Toronto Blue Jays.
Rookie Bryce Harper continued his impressive form with another home run, Jhonatan Solano registered his first major league homer and Danny Espinosa clubbed a two-runner to see off the Jays.
The Texas Rangers remain in control of American West following a 9-1 hammering of the Arizona Diamondbacks.
Colby Lewis pitched a full game for one run on four hits and received plenty of assistance from his batters, who tallied 16 hits.
The pitchers had a day to forget as the Minnesota Twins defeared the Philadelphia Phillies 11-7 in a match that yielded a total of 31 hits.
The Twins had the best of things - Denard Span, Trevor Plouffe and Josh Willingham all homering.
The New York Mets also scored freely in their 11-2 success over the Tampa Bay Rays.
Ike Davis struck a three-run homer and Jordany Valdespin drove in four to deliver the win for starter Chris Young.
The Chicago Cubs stole a 4-3 victory over the Detroit Tigers, with three-RBI Darwin Barney securing the winner after shortstop Jhonny Peralta's poor throw.
The Cincinnati Reds rode a full game from Johnny Cueto for a 7-1 win over the Cleveland Indians.
The Baltimore Orioles beat the Pittsburgh Pirates 8-6, the Oakland Athletics saw off the Colorado Rockies 8-5 and the Kansas City Royals edged the Milwaukee Brewers 2-1.
The Boston Red Sox were 2-1 winners at the Miami Marlins, the Houston Astros went down 6-3 at the hands of the San Francisco Giants, the San Diego Padres beat the Seattle Mariners 5-4 and the Chicago White Sox were 6-1 victors over the St Louis Cardinals.
