Kessel, still unpopular in Boston for holding out until he was traded in 2009, was booed throughout the night. He jumped on a turnover by Zdeno Chara at the blue line, got around Andrew Ference for a mini-breakaway and faked out Thomas with a forehand shot to tie the game with 6:33 remaining.
The game appeared headed for overtime until Grabovski, who was dazed by Chara on a headfirst hit into the boards in the first period, took a pass from Clarke MacArthur in his own zone, beat two defensemen and fired a sharp-angled shot past Thomas.
"I was trying to take him and the guy cutting to the back door instead of just taking the shot," Thomas said. "So I left an opening and he took it."
"I like play like that," Grabovski said. "I like when defensemen play hard against me. It gives me motivation, and I play harder and faster."
Bergeron broke a 2-all tie with an even-strength goal with 10:52 left. Adam McQuaid fired a shot from the point and Bergeron was in place for the rebound despite getting smothered by defenseman Dion Phaneuf as he poked the puck into the net for his first goal in five games.
Grabovski, who drew a penalty when he was driven into the boards by Chara in the first, put Toronto up 2-1 early in the second on a lucky bounce off Boston defenseman Steven Kampfer's leg for a wide-open backhand.
The Bruins tied it at 2 with 1:26 to go in the first on a power-play goal. Reimer couldn't handle a shot from the slot by Brad Marchand and the rebound bounced up in the crease, where Campbell knocked it in. The play withstood a video review.
Kessel's first goal was also on a high rebound, but his stick was below the crossbar and the goal was deemed OK. The Maple Leafs were already on a power play when Chara was called for boarding, giving Toronto 1 second of a 5-on-3 advantage. That was enough time for the Leafs to win the faceoff and get a shot from Lupul, who hit Thomas. But the puck bounced right to Kessel for a mid-air one-timer -- his first goal ever against his former team.
Paille, coming off a four-game suspension for a blind-side hit on Dallas' Raymond Sawada on Feb. 3, put Boston up 1-0 with 11:56 left in the first when the puck deflected off a Toronto player's skate.
After the game, the Bruins acquired forward Chris Kelly from the Ottawa Senators in exchange for a second-round pick in the 2011 Entry Draft.
Material from wire services and team media was used in this report.
|Daniel Paille (2) ASST: Mark Stuart (4), Gregory Campbell (12)|
1 - 0 BOS
|PPG - Phil Kessel (20) ASST: Dion Phaneuf (12), Joffrey Lupul (9)|
1 - 1 Tie
|Mikhail Grabovski (23) ASST: Mike Komisarek (9), Carl Gunnarsson (6)|
2 - 1 TOR
|PPG - Gregory Campbell (8) ASST: Brad Marchand (15), Michael Ryder (18)|
2 - 2 Tie
|Patrice Bergeron (20) ASST: Adam McQuaid (8), Mark Recchi (29)|
3 - 2 BOS
|PPG - Phil Kessel (21) ASST: Joffrey Lupul (10), Tomas Kaberle (34)|
3 - 3 Tie
|Mikhail Grabovski (24) ASST: Clarke MacArthur (28), Dion Phaneuf (13)|
4 - 3 TOR
|David Krejci Hooking against Clarke MacArthur|
|Zdeno Chara Boarding against Mikhail Grabovski|
|Dion Phaneuf Slashing against Milan Lucic|
|Keith Aulie Interference against Tyler Seguin|
|Mikhail Grabovski Hi-sticking against Mark Stuart|
|Dennis Seidenberg Cross checking against Dion Phaneuf|
|Keith Aulie Hooking against Michael Ryder|