The Baltimore Orioles jumped back into a tie for the lead with the New York Yankees in the American League East Division after taking down the Boston Red Sox 4-3 on Saturday as the Yankees stumbled 3-2 to Toronto.
With the regular season just four games away from completion, the Orioles joined the Yankees on a 91-67 record thanks to a Manny Machado home run in the seventh, his blast over left field breaking a 3-3 deadlock.
Earlier the Orioles had jumped out to a 3-0 lead through four innings thanks in part to Chris Davis's 30th home run of the season but Boston tied things up after six before Machado proved the hero.
The Yankees had plenty of chances to stay ahead in the divisional race but could not put enough runs on the board.
New York scored two in the first inning but failed to post another run all night as the Blue Jays notched up runs in the first, fifth and sixth innings.
"Tomorrow is going to be a must-win," Yankee Nick Swisher said. "We put ourselves in this situation and destiny in our own hands. We've got to go out and take it. No one is going to give us anything."
The losers of the divisional race still have a good chance of a wildcard berth but are not yet guaranteed a place in the post-season.
Two wildcard sides will fight out in a one-game playoff with the winner joining the division champions in the post-season.
Oakland currently hold the second wildcard position a game back after a 7-4 win over Seattle but could also still win the AL West as they pulled within 2.5 games of the Texas Rangers.
The Los Angeles Angels sit 2.5 games behind the Athletics in the wildcard race and Tampa Bay maintain the faintest of hopes - three games back after a 10-4 win over the Chicago White Sox.
The Angels were due to play the Rangers on Saturday but rain ensured the game was postponed, forcing the teams into a Sunday double-header.
The White Sox loss to the Rays allowed the Detroit Tigers to open up a two-game lead in the American League Central after they downed Minnesota 6-4.
Leading 6-0, Detroit wobbled when Twin Ryan Doumit powered a grand slam in the bottom of the eighth to pull within two runs but the Tigers held on for an important victory.
"It hasn't lacked for excitement," Tigers manager Jim Leyland said of the divisional race.
Leyland admitted to a small bout of nerves after the Twins eighth inning rally.
"The heart starts pumping a little faster, obviously. That's a good thing," he said. "If it don't pump at all, that's not good."
The White Sox were extremely disappointing at home, trailing 10-0 until the bottom of the eighth.
They grabbed four runs in the penultimate inning but it was too little, too late and could be the death knell to their year.
In the National League, the final wildcard spot remains up for grabs after the St Louis Cardinals fell 6-4 to Washington.
The loss, coupled with the Los Angeles Dodgers 3-0 win over Colorado, allowed the Dodgers to pull within two games with four to play.
Washington's win did everything but officially clinch the National League East division, as they are now four games clear of the Atlanta Braves.
The Braves won 2-0 over the New York Mets and, while they need a miracle to win the division, are already assured of the first wildcard place.
Cincinnati (Central) and San Francisco (West) won their divisional races earlier this month.
(Reporting by Ben Everill in Los Angeles, editing by Nick Mulvenney)