Ryan O'Reilly and Zemgus Girgensons scored 2:05 apart in the second period in the Buffalo Sabres' 5-3 win over the Maple Leafs, who lost their fourth straight.
Sam Reinhart, Jason Pominville and Johan Larsson also scored for Buffalo.
The Sabres improved to 7-5-2 in their last 14, a stretch in which the Eastern Conference's last-place team continues playing havoc with playoff contenders.
Buffalo has now defeated each of the Atlantic Division's three top teams, including Boston twice, over the past three weeks.
Leo Komarov had two goals and Mitch Marner also scored for Toronto. The Maple Leafs dropped to 0-2-2 in their past four to match their longest skid of the season.
Frederik Andersen stopped 19 shots in allowing five goals for the second consecutive outing after being yanked midway through a 5-2 loss to Washington on Saturday.