Luol Deng hit a jumper with 3.3 seconds to play in overtime as Chicago escaped Toronto with a 107-105 victory on Wednesday.
Deng finished the game with 19 points, seven assists and six rebounds while Carlos Boozer had a season-high 36 points with 12 rebounds for the Bulls, who have won three of four.
Alan Anderson had 27 points and five boards while Kyle Lowry gave 26 points, seven assists and five rebounds for the Raptors, who have dropped their last three games.
"We played hard after not playing well in the third quarter," said Lowry. "We made the plays we needed to get back into the game, just fell a little short at the end."
Chicago held a 19-point lead in the third quarter, but Toronto methodically chipped away and tied the game at 100 after Amir Johnson hit one-of-two from the foul line with 12.1 seconds to play.
The scoring was slim in the extra session and the Bulls had a one-point lead when Marco Belinelli was fouled with 15.1 seconds to play. He made the first shot, but missed the second and Lowry followed with a floater at the other end to tie the game with 8.7 seconds left.
Following a timeout, Deng had the ball inside the 3-point line and buried a fadeaway jumper for a 107-105 lead with 3.3 seconds left.
"I tweaked my hamstring early in the first quarter and took some time off," said Deng. "Coach kept asking me if I was OK and after a little rest I was fine. I was just trying to get as good of a look as I could and got lucky."
Johnson held the ball and drove the lane, but was fouled by Joakim Noah with one second left. Jose Calderon received the inbound pass from beyond the arc, but his shot at the buzzer didn't go down.
Chicago used an 8-0 run in the first quarter to take a 29-22 lead after the first 12 minutes and, despite briefly losing the lead in the second quarter, held a 52-44 advantage at the halftime break.
A Richard Hamilton 3-pointer with 4 1/2 minutes left in the third gave the Bulls a 76-57 lead, but Toronto closed the quarter with a 16-3 run to cut its deficit to 79-73 lead heading to the fourth quarter.
Chicago led by as many as 10 in the fourth quarter before giving up the advantage down the stretch.