Pyatt took advantage of a Matt Duchene rebate in a three-on-one run to beat Frederik Andersen on the shield side.
Thomas Chabot, Mike Hoffman and Gabriel Dumont also hit the target for the Senators, who took an 8-2 loss to the Chicago Blackhawks the night before.
Craig Anderson repelled 44 shots in the win as he was thrown out of the net against the Blackhawks.
“He only played 30 minutes and it gave him the chance to come back the next day,” said Senators head coach Guy Boucher about Anderson. I was confident to see him bounce back and that’s what he did.”
Anderson had four goals on 26 shots against the Blackhawks.
“You have to turn the page as quickly as possible,” said Anderson.
Andreas Borgman, James van Riemsdyk and Morgan Rielly generated the Maple Leafs offensive, while Andersen made 29 saves.
“We had a lot of chances, but we lost patience,” said Maple Leafs head coach Mike Babcock. Twice, our defenders were too aggressive and it cost us two goals. You have to play the right way. ”
Maple Leafs center-right Auston Matthews kicked off the game, creating three scoring opportunities in the opening minutes of the game. He even reached the horizontal bar once.
Chabot opened the scoring after 11:26 of play, when his cross pass attempt deflected against defender Roman Polak’s foot before surprising Andersen.
Hoffman broke the gap after 1:52 in the second period. He ignored van Riemsdyk’s cover in the net and completed a game started by Duchene.
The Maple Leafs were unable to beat Anderson in the first 36 minutes despite three power-play goals and 28 shots on goal, including eight by van Riemsdyk.
Borgman finally surprised Anderson with 1:50 to make the second twenty thanks to a shot from the edge. Van Riemsdyk then tied after 56 seconds of play in the third period, on his ninth shot of the game.
Dumont gave the Senators the lead just 1:21 later, but Rielly brought everyone back to square one at 12:28.
Rielly, however, was too aggressive in the Senators blue line on Pyatt’s winning goal sequence. He compromised himself by stealing the record from a rival, but instead allowed Pyatt to launch the assault. Pyatt quickly handed Duchene to his right, then defender Ron Hainsey compromised in turn by wanting to cut Duchene’s space. The latter joined Pyatt late alone in the enclave and the support striker skillfully foiled Andersen.