Nic Petan and Nikita Zaitsev scored goals for the Maple Leafs in the final five minutes of the second period to break what had been a 2-2 tie. Petan buried a one-time shot from the slot; Zaitsev scored with a shot from the half wall that deflected in off the skate of Sabres defenseman Brandon Montour.
Zaitsev's goal could be chalked up to an unfavorable bounce, but Housley pointed to Petan's go-ahead marker as a breakdown in defensive coverage. Trevor Moore won a puck battle with Rasmus Ristolainen, who had two men on him behind the Buffalo net, and found Petan all alone in the slot.
"I think it's just communication," Housley said. "We're all marked up on our guys and they just move it high to low. It's unfortunate. We're getting the puck on the wall, and now we talk about sensing that danger and just realizing that doesn't look good, being alert that it could get turned over."
The Sabres led 2-1 in the first period, when Pominville and Sheary both scored goals within 3:14 of John Tavares' opening marker. They had chances to extend their lead, too. Andersen stopped a turn-around shot from Jack Eichel as well as a rebound from Skinner, and Sam Reinhart rung a shot off the post.
Instead, the Maple Leafs tied the game on a shot from the point by Morgan Rielly that found its way through traffic and crept in between Ullmark's pads with 18.4 seconds left in the period.
"It was a big key," Housley said. "We go into the period 2-1, we certainly have an advantage stepping into the second period. We get a lot of good looks in the first period."
Maple Leafs forward Patrick Marleau bumped Ullmark as he battled for position with Evan Rodrigues, but Housley decided not to challenge for goaltender interference as it appeared Rodrigues had forced the contact.
"I just thought they got inside position and ... [Rodrigues] was pushing their player into our goalie," Housley said. "I just felt that we weren't going to win that challenge."
Ullmark said he agreed with the call on the ice.
"It's kind of a playoff hockey sensation when we play right now, so things are going to get rougher in front of the net," Ullmark said. "For me, you've just got to keep on battling."
Despite the late goals allowed in each of the first two periods, the Sabres came into the third with the sort of effort that propelled them to a comeback win against Pittsburgh on Friday. Andersen held long enough for Mitch Marner to score into an empty net with 1:57 remaining.
"We're not going to quit," Pominville said. "We know that we've got to get every point we can. I thought we threw everything at them. We unfortunately weren't able to put one in. Definitely had some looks and not a lot of puck luck in the third. I don't think it was from a lack of effort or execution. The goals we gave up were at costly times and we weren't able to rebound from it."
