Kessel's third goal of the game with 2:19 remaining negated Ottawa's third-period comeback from a four-goal deficit as the Leafs held off the Senators 6-5 on Saturday night to win for the second time in as many tries this season.
Kessel scored twice as the Leafs took a 4-0 lead after two periods, and Toronto led 5-1 when Colton Orr scored 2:52 into the third period. But the Senators got a pair of goals from Daniel Alfredsson sandwiched around one by Jason Spezza to cut Toronto's margin to just one goal with 4:16 remaining.
Kessel completed his hat trick with what proved to be the winning goal when rookie Stephane da Costa beat James Reimer with 1:56 remaining.
"I'm playing with good linemates," Kessel said. "They're getting the puck in good areas to me, and I was able to bury them."
Ottawa's comeback turned a one-sided affair into a close call -- one that the Leafs need to take a lesson from, according to captain Dion Phaneuf,
"We played really well for 40 minutes, 50 minutes, but we took our foot off the pedal and they came hard. We need to learn from that. But it's a big two points and we'll take them."
It was the second time in as many nights that the Senators rallied after digging themselves a huge hole. They trailed 5-0 early in the third period at Detroit on Friday before losing 5-3.
"Even if we're in a tough position we're not going to quit as a team," Alfredsson said. "Once you get momentum it's hard to turn it around -- but we would like to start the game with that momentum and put ourselves in front. We'll be a better team and have a chance to get some more points."
After a sluggish start, the Maple Leafs opened the scoring at 12:58 of the first period when Mikhail Grabovski converted a slick pass from Nikolai Kulemin for a power-play goal. The Leafs gained momentum as the period went on, and added to their lead at 18:51 when Joffrey Lupul fed Kessel on a 2-on-1 and Kessel beat Craig Anderson.
Phaneuf leveled Da Costa with a thundering open ice body check early in the second period, eliciting chants of "Dion, Dion" from the Air Canada Centre crowd. Chris Neil tried to rally the Senators by pummeling Luke Schenn, but received 19 minutes in penalties for his efforts.
The Leafs quickly capitalized on the four-minute power play, going up 3-0 at 7:56 when Lupul deflected John-Michael Liles' point shot past Anderson. Kessel made it 4-0 on a fine individual effort at 18:49.
"You don't like to see one of your teammates get hit like that," Neil said. "It was a pretty big hit for them."
However, Ottawa coach Paul MacLean had no problem with the hit.
"You have to accept a certain amount of risk when you play this game," he said. "I know I'd never come across (the middle of the ice) like that.
"I thought the hit was clean and I expected no other response other than the one we had on the ice."
Colin Greening ended Reimer's bid for a second straight shutout at 1:42 of the third, but Orr made a triumphant return to the ice with his 11 th career goal, scoring in his first game back since suffering a season-ending concussion in January.
"I'm hoping it was all a dream and I'm going to go out there for the third period," said Reimer, who blanked Montreal 2-0 in the Leafs' opener on Thursday and had his shutout streak broken at 101:42 when Greening scored. "But, you know what, a win's a win.
"It sure wasn't pretty, but the fans got their money's worth and we got the two points."
The winless Senators head back to Ottawa to prepare for their home opener Tuesday against Minnesota, while the Leafs are off for a week before hosting the Flames next Saturday night. They will spend three days at Canadian Forces Base Trenton for team building activities and on-ice practice.
While coach Ron Wilson acknowledged that it would be nice to keep the team's momentum rolling, he stressed the positives of the upcoming trip,
"We'll have a good week where we're spending time together," he said. "That's as much a positive because we haven't spent a night in a hotel yet or really together doing team activities. So it's going to be a great week for us."