It was the Bobcats' first win since beating Golden State 112-100 on Jan. 14 -- over a month ago.
"It's big, we're excited about it," Augustin said. "We've been losing a lot. That's not a great feeling. But to win, it feels good."
"Unbelievable," Bobcats coach Paul Silas said of Biyombo's performance. "He let it all out tonight. Thirteen rebounds, seven blocks. Just outstanding."
Corey Maggette added 16 points as Charlotte avoided becoming the 28th team in NBA history to drop at least 17 straight games on the same day that Jordan, their majority owner, turned 49.
"It's just really good to get the monkey off our back," Maggette said. "It feels great. The last 16 times, we've come in the locker room with our heads down. It's good to see our guys really continue to work and stay positive."
At 4-26, the Bobcats remain the NBA's worst team, three victories behind the New Orleans Hornets. Still, that didn't spoil the celebrations after this one.
"Even though it's only our fourth win, it's just a win," Walker said. "A win is a win. It's been a while. We're overdue. We came in, played tough and pulled it out."
All of Williams' points came in the first three quarters. He did not play in the fourth.
"The two guys I had were going really well, Kemba and D.J. Augustin," Silas explained. "I just decided to stay with them."
DeMar DeRozan scored 24 and Leandro Barbosa 16, while Amir Johnson had a career-high 15 rebounds for the Raptors, who have lost four straight and 10 of 13. Toronto has lost five straight to Charlotte and is 4-11 at home this season.
"Totally disappointed in our focus in the first half," Raptors coach Dwane Casey said. "We didn't really think it was going to be an offensive battle. We'd get our points and then not guard our guy at the other end."
Trailing 69-68 after three quarters, the Bobcats opened the fourth with an 11-2 run, forcing Toronto to call timeout after Augustin's driving layup made gave Charlotte a 79-71 edge with 8:53 left.
Calderon stopped the run with a 3 and Ed Davis added a dunk. But the Bobcats held firm, scoring six of the next eight points to lead 85-78 with 5:58 to go.
Down 90-88, the Raptors were driving for the tying basket inside the final two minutes when Walker forced a steal from Barbosa. At the other end, Barbosa fouled Maggette, who made a pair from the line to put Charlotte up by four at 92-88 with 1:37 left.
"He was coming at me full-speed and I was just trying to get my hand in there," Walker said of the vital steal. "I got a piece of the ball and it went out of bounds off him."
DeRozan banked in a jumper but Walker found Boris Diaw for a baseline shot, restoring the four-point cushion. DeRozan was fouled and made the first but missed the second, with Walker grabbing the rebound for the Bobcats. That led to D.J. White's layup with 15 seconds left, giving Charlotte a 96-91 lead.
Toronto's inbounds play went wrong when Calderon's lob pass ended up in the basket, sending the ball back to the Bobcats. Maggette sealed it with a pair of free throws.
Charlotte made 12 of 13 from the free throw line in the final quarter.
Williams scored 14 points in the opening quarter, but DeRozan had 13 for the Raptors, who led 23-22 after one.
James Johnson had 10 points and five rebounds for the Raptors in the second but it was the Bobcats, thanks to five points each from Augustin and Maggette, who held a narrow 47-45 lead at the half.
DeRozan had to leave the game midway through the third after colliding with Maggette and being called for a charge, his fourth personal foul. DeRozan stayed down clutching his face and received treatment on the court before walking to the bench.
Walker scored seven points in the third, including a driving layup with 6 seconds left, but Barbosa's seven points gave Toronto a slender 69-68 edge heading into the final quarter.
Bobcats G Gerald Henderson (strained right hamstring) is not expected to return until next Wednesday's home game against Indiana. ... Bayless returned after missing four games with a sore left ankle. ... Raptors F Linas Kleiza (left knee) missed his second straight game.