Yoenis Cespedes also went yard for the As who have now won four straight games to move to 79-58 for the season, the same record as their opponents.
It is a straight fight between the sides for the West crown, with the third-placed Los Angeles Angels 14.5 games back.
The Angels thrashed the Tampa Bay Rays 11-2 on Monday with Erick Aybar swatting a home run and four RBI.
The other two sides in the division, Seattle and Houston, are not factors in the post-season shake-up.
On Monday, Labor Day in the United States, Seattle went down 3-1 to Kansas City while Houston lost 10-6 to Minnesota, for whom Chris Colabello hit a go-ahead grand slam in the ninth inning.
Detroit continue to lead the way in the AL Central, a 3-0 win over AL East table-toppers Boston increasing their advantage to 8.5 games over Cleveland.
Tigers starter Doug Fister blanked the Red Sox through seven innings to register his 12th win of the year.
Bud Norris twirled seven innings of one-run ball to give his Baltimore side a 7-2 win over Cleveland.
Nate McLouth and Matt Wieters each hit two-run homers for the Orioles.
Atlanta rode the hot bat of Freddie Freeman to continue to set the pace in the National League East.
Freeman hit a two-run double in the first and a three-run homer in the second as the Braves downed the New York Mets 13-5.
Closest challengers Washington were edged out 3-2 by Philadelphia, for whom Carlos Ruiz delivered two RBI including the go-ahead single in the eighth.
Jose Tabata had two RBI and Neil Walker hit a three-run homer as Pittsburgh claimed sole possession of first place in the NL Central with a 5-2 win over Milwaukee.
Pirates pitcher Charlie Morton had a sixth straight quality start to move his side a game ahead of the St Louis Cardinals, who went down 7-2 at Cincinnati.
Reds starter Mat Latos pitched his first complete game of the season and Shin-Soo Choo and Joey Votto each hit home runs off Cards ace Adam Wainwright.
NL West leaders the Los Angeles Dodgers won a wild encounter with the Colorado Rockies 10-8 while Toronto beat Arizona 4-1, San Diego beat San Francisco 4-1, Miami beat the Chicago Cubs 4-3 and the New York Yankees eased past the Chicago White Sox 9-1.