Jonathan Lewis struck at the death as New York City trumped New England Revolution, while reigning MLS Cup champions Seattle Sounders converted a last-gasp penalty against Minnesota United.
Lewis scored in the fourth minute of stoppage time to give hosts New York a last-gasp 2-1 victory on Sunday.
NYC were forced to come from behind against the visiting Revolution, who took a 57th-minute lead through Teal Bunbury.
But New York were back on level terms 20 minutes later when the league's top goalscorer David Villa took his tally to 19.
Former Spain international Villa was on hand to fire the ball home from just outside of the six-yard box.
Lewis then riffled his shot into the back of the net to give New York their third consecutive victory, enough to keep them second in the Eastern Conference and four points adrift of leaders Toronto FC.
The Revolution, meanwhile, are second from bottom in the east and seven points adrift of the play-off places.
There was also a dramatic finish in Seattle as the Sounders defeated Minnesota 2-1 at CenturyLink Field.
Ethan Finlay put Minnesota ahead in the 21st minute, but Chad Marshall replied for the visitors just past the half-hour mark.
But Clint Dempsey scored a 94th-minute penalty as Seattle extended their unbeaten streak in MLS to seven matches.
Expansion franchise Minnesota, meanwhile, are yet to win away from home this season - a run of 10 games.