Kadri's goal lifts Maple Leafs past Sabres, 3-2
David Steckel and Phil Kessel also scored for Toronto and James Reimer had 40 saves.
Kadri, recalled from Toronto of the AHL on Wednesday after a 22-game stint in the minors, got his first goal of the season when he scored off Buffalo goalie Ryan Miller's glove at 5:52 of the third.
Jason Pominville and Derek Roy scored for the Sabres. Pominville gave Buffalo a 1-0 lead with his 11th goal of the season on the power play at 11:49 of the second. After Steckel and Kessel put the Maple Leafs ahead later in the period, Roy tied the score at 1:29 of the third.
The first period belonged to Miller, who had his play questioned by Sabres owner Terry Pegula following a blowout loss in Pittsburgh last weekend.
With the Leafs off to a fast start, Miller stopped Kessel at the side of the goal before getting his shoulder on Matt Frattin's one-timer. Toronto was unable to score on any of its 12 first-period shots.
The momentum swung early in the second as Toronto took four straight penalties, including a delay of game call to Tyler Bozak that left the team two men short for 67 seconds. Reimer overcame a barrage of shots, only allowing a goal to Pominville when the Sabres' captain saw his shot deflect off in Leafs defenseman Luke Schenn.
The Leafs responded with a goal from their little-used fourth line. Playing just their second shift of the period, Steckel dribbled a shot past Miller from the top of the crease at 15:52.
That brought the sellout crowd to life, with fans derisively chanting: "Millller! Millller!" when Kessel made it 2-1 just over a minute later. The flashy winger scored his 20th of the season after taking a nice pass from linemate Joffrey Lupul.
The lead was short-lived as Roy tied it early in the third period. He grabbed the puck on a turnover at the Leafs blue-line and beat Reimer to the glove side.
Kadri's winning goal was an important one for a Leafs team that has been sliding of late. They won for just the third time in 10 games and gained valuable points on a division rival that they'll likely be battling for a playoff spot down the stretch.
Buffalo is also reeling as it heads into the Christmas break. The banged-up team can use the time off as leading scorer Tomas Vanek left in the third period, making it seven regulars out of the lineup.
NOTES: Fans booed an in-game promo featuring Canadian pop phenom Justin Bieber, who skated with the Leafs on Wednesday. ... Kessel has 20 or more goals in four straight seasons. ... Patrick Kaleta returned to Buffalo's lineup after missing 12 of the last 13 games with a groin injury. ... Toronto is 11-0-0 when leading after two periods.