Kevin Youkilis' three-run homer lifted the American League Central-leading Chicago White Sox to a 7-5 victory over the Boston Red Sox at Fenway Park on Tuesday.
Youkilis, traded to Chicago by Boston less than a month ago, connected in the fourth inning to frustrate his former teammates and earn the White Sox their eighth win in 11 games.
Andruw Jones also had a three-run homer on Tuesday, and CC Sabathia threw six shutout innings, as the AL East-leading New York Yankees overcame the Toronto Blue Jays 6-1.
Mike Trout had four hits, including a homer, in the Los Angeles Angels' 13-0 thrashing of the Detroit Tigers, while three hits and two RBI from Jesus Montero powered the Seattle Mariners to a 9-6 triumph over the Kansas City Royals.
In other AL action, the Minnesota Twins defeated the Baltimore Orioles 6-4, the Tampa Bay Rays toppled the Cleveland Indians 4-2 and the Texas Rangers prevailed 6-1 against the Oakland Athletics.
Ryan Zimmerman hit the decisive run for Washington on a wild pitch with two outs in the 10th as the National League East-leading Nationals rallied for a 5-4 win over the New York Mets.
NL West-leading San Francisco hammered the Atlanta Braves 9-0, Buster Posey driving in five runs including a three-run double in the fourth inning for the Giants.
Carlos Lee hit a grand slam in the Miami Marlins' 9-5 success against the Chicago Cubs, while Johnny Cueto pitched six scoreless innings in the Cincinnati Reds' 4-0 win over the Arizona Diamondbacks.
Elsewhere in the National League on Tuesday, the Pittsburgh Pirates beat the Colorado Rockies 6-2, the Milwaukee Brewers scraped past the St Louis Cardinals 3-2, the San Diego Padres won 8-2 against the Houston Astros and the Philadelphia Phillies edged out the Los Angeles Dodgers 3-2.
