"I just wanted to come in with a lot of energy," Lucas said. "The first half I felt like I was flat and I wanted to make it up. I said `I'm just going to give it everything I have and just go out there and play my hardest and leave everything on the court."'
Lucas has reached double figures in three of the past five games after doing so just six times in the previous 44 games.
"He's getting more comfortable out there the more he's playing," Deng said. "He's capable of hitting shots and we do a good job of recognizing that and making sure he gets his looks."
Kyle Korver also came up big in the fourth, scoring all of his 10 points in the quarter as the Bulls came back after trailing by 12 early in the second half.
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"We're so deep that there's always guys somehow, somewhere, who are going to get it going," Deng said.
Korver also praised Chicago's depth.
"This team, we have a lot of pieces that fit really well together," Korver said. "We all have different strengths and we try to play to our strengths. I think the fourth quarter tonight was about as well as you can do at playing to strengths."
C.J. Watson scored 15 points and Ronnie Brewer had 12 for the Bulls, who won their third straight. League-leading Chicago (39-10) has won six of eight since an eight-game winning streak from Feb. 20 to March 7.
"You have to win games different ways," coach Tom Thibodeau said. "If you're going to be a good team, that's what you have to do."
The Bulls outscored the Raptors 32-13 in the fourth to win their sixth straight road game, improving to an NBA-best 20-6 away from home. Chicago's last road loss was Feb. 12 at Boston.
The Bulls also won for the fourth time in five games without leading scorer Derrick Rose, who is still sidelined with a sore right groin. Thibodeau said Rose has not yet resumed running.
"He's doing more and more," Thibodeau said. "He's doing some shooting. He's moving right along."
"They're one of the best defensive teams in the league," Raptors coach Dwane Casey said. "We didn't execute. When you know that a championship team is turning up the screws, you have to make every play. There's no room for negotiations."
Andrea Bargnani made two of his 10 field goal attempts and finished with eight points. His six assists were one shy of a career high.
Jose Calderon also struggled with his shooting, going 3 of 10. He had nine points and eight assists.
Toronto made just four of 18 shots in the fourth.
Lucas scored Chicago's first seven points of the final quarter, including a 3-pointer with 8:10 left, cutting Toronto's lead to 72-69 and forcing the Raptors to call timeout.
After Gary Forbes missed a shot, Lucas fed Korver for a game-tying 3. At the other end, Omer Asik blocked Linas Kleiza's driving jumper, setting up Taj Gibson for a go-ahead dunk. Lucas and Korver each hit jumpers on the next two possessions and Chicago didn't trail again.
Toronto's only basket in the first 8 minutes of the fourth was a hook shot by Ed Davis, who converted the three-point play with 10:28 left. The Raptors, who missed 10 of their first 11 shots in the quarter, didn't score again until a pair of free throws by Bargnani with 3:28 to play, by which time their 72-64 lead had become an 84-74 deficit.
Raptors guard Jerryd Bayless, who was knocked out of Tuesday's loss at New York after injuring his left hip in a collision with Carmelo Anthony, had to leave this one after playing just 1:29 in the opening quarter.
Deng scored Chicago's first seven points of the game and had 10 in the first quarter as the Bulls led 27-23. Former Bulls center Aaron Gray had five rebounds and six points as Toronto outscored Chicago 28-16 in the second to lead 51-43 at the half.
DeRozan and Brewer each scored six points in the third as the Raptors took a 69-62 lead into the final quarter.
- The Bulls are 11-4 without Rose this season.
- In their two meetings this season, Chicago has outscored Toronto 53-25 in the fourth quarter.
- The Raptors honored the Canadian Forces by becoming the first NBA team to wear camouflage jerseys, the first of four occasions they'll wear them. More than 300 members of Canada's military attended the game.
- The Raptors are home against New York on Friday night while Chicago is off until Saturday, when the Bulls host Toronto for the third and final meeting of the season.