The Los Angeles Dodgers won the National League's West division with a 9-1 thrashing of MLB rivals the San Francisco Giants on Wednesday.
Dodgers pitcher Clayton Kershaw struck out 11 in eight innings pitched, and also hit his first career triple as they sealed consecutive divisional crowns.
The Giants, meanwhile, are yet to assure themselves of a wildcard spot, after the Milwaukee Brewers routed the Cincinnati Reds 5-0 to stay alive in the post-season race.
The Brewers, though, are four games behind the Giants with four to play, meaning they must sweep the Chicago Cubs and also win their series finale with the Cincinnati Reds and hope the San Diego Padres sweep San Francisco in their four-game series.
Neither the St Louis Cardinals nor the Pittsburgh Pirates won, leaving their NL Central division fight on a knife's edge.
The Cardinals were beaten 3-1 by the Chicago Cubs, while the Pirates - 1.5 games behind but assured of a wildcard - lost 6-2 to the Atlanta Braves.
In the American League, the Detroit Tigers sealed their post-season spot and loomed on the Central title with a 6-1 win over the Chicago White Sox.
The Tigers' rivals the Kansas City Royals fell to a 6-4 loss to the Cleveland Indians, a defeat that leaves them two games behind Detroit.
Kansas City and the Oakland Athletics remain poised to play-off in the wildcard match-up, although Cleveland and the Seattle Mariners remain outside chances of getting in.
The Mariners lost for the fifth straight time, though, going down 1-0 to the Toronto Blue Jays to miss their chance to gain ground - leaving them three games behind the Royals and A's.
San Diego are in winning form, the Padres edging the Colorado Rockies 4-3 to set the record for their most home wins at Petco Park (48) in one season.
The Texas Rangers were 5-1 winners over the Houston Astros, the Boston Red Sox thrashed the Tampa Bay Rays 11-3, the Philadelphia Phillies edged the Miami Marlins 2-1, the Los Angeles Angels were 5-4 victors against the Oakland Athletics, the Minnesota Twins edged the Arizona Diamondbacks 2-1 and the Baltimore Orioles were 9-5 winners over the New York Yankees.
The New York Mets' scheduled clash with the Washington Nationals was postponed.