Kadri's physical shift helped slow Washington's momentum, and Toronto was able to rally to win 4-3 when center Tyler Bozak scored at 1:37 of overtime.
The Maple Leafs lead 2-1 in the best-of-7 series, which continues with Game 4 here Wednesday (7 p.m. ET; NBCSN, CBC, TVA Sports 2, CSN-DC).
"That was a huge shift for the entire team," said Maple Leafs forward William Nylander, who watched Kadri's shift from the bench before taking the ice with Matthews. "I think it got the building going and gave us a little bit of momentum. It was great to see those guys go out and do a great job. You want to get out there and try to take over the game the way they did."
Maple Leafs defenseman Jake Gardiner, who was on the ice for half of Kadri's shift, agreed it was a turning point.
"That was huge," he said. "Kadri] has been a leader for us all year. He's one of those guys who makes big plays and that was an example of it. He didn't score a goal or anything [on that shift], but he got the crowd involved and it kind of energized our bench."
***[RELATED: [Complete Maple Leafs vs. Capitals series coverage]*
Capitals coach Barry Trotz said Kadri's physicality helped swing the momentum to the Maple Leafs, but he pointed to moments Washington did not seize, including a two-minute 5-on-3 power play in the second period, when a goal would have put the Capitals ahead 4-1.
"[Kadri] got the crowd into it so they're going to say it's a momentum-changer," Trotz said. "We had a 5-on-3 that we didn't capitalize on, that was a momentum-changer too for them. There's different moments when two teams are battling, we've obviously gone to three games of overtime, so there's not much room.
"There's going to be a shift or two that will change momentum, and then we'll do something well and it will give us momentum and zone time and the momentum will swing right back to us. When that happens, you've got to find a way to get it back. For them, the crowd was a little quiet, they had a couple of big hits, the crowd got into it and they like the physical play up here in Toronto."