Hawes scored 10 points in the fourth quarter for the eighth-seeded Sixers.
Game 4 is Sunday in Philadelphia.
Already playing the rest of the series without reigning MVP Derrick Rose, the Bulls got another scare in the third quarter when Joakim Noah left with a sprained left ankle. Noah, who scored 12 points, returned in the fourth quarter and mostly hobbled around the court.
The Sixers scored only 11 points in the third quarter and trailed by double digits early in the fourth.
Hawes hit a 20-footer for a 72-71 lead and Evan Turner made two free throws for a three-point lead with 1:24 left. John Lucas III of the Bulls buried a 3-pointer to make it a one-point game. Jrue Holiday hit two free throws to seal the win.
Carlos Boozer had 18 points and 10 rebounds for the Bulls and Richard Hamilton scored 17 points.
CELTICS 90, HAWKS 84, OT
BOSTON (AP) — Rajon Rondo had a triple-double with 17 points, 14 rebounds and 12 assists to lead Boston which took a 2-1 lead in the first-round playoff series.
It was the seventh career playoff triple-double for Rondo, who missed Game 2 because he was suspended for bumping a referee in the closing minutes of the series opener.
Game 4 is Sunday night.
Ray Allen returned for Boston after missing almost a month and scored 13 points in 38 minutes. Kevin Garnett had 20 points and 13 rebounds, and Paul Pierce had 21 points.
Joe Johnson scored 29 points and Jeff Teague had 23 for the Hawks. Tracy McGrady had 12 points — his highest total since he had 40 for Houston in 2008 — but 10 were in the first half, before he landed awkwardly on his right ankle.
The Celtics went on an 11-1 run to open a double-digit lead with 7 minutes to play in regulation, but Atlanta tied it 80-80 on Johnson's 3-pointer with 1:23 left. Pierce took a long, fallaway jumper that bounced off the rim at the buzzer.
NUGGETS 99, LAKERS 84
DENVER (AP) — Ty Lawson scored 25 points and Denver raced to an early 24-point lead in Game 3 of the first-round series.
JaVale McGee had 16 points and 15 rebounds for the Nuggets, who will try to even the best-of-seven series at two games each on Sunday night at the Pepsi Center.
The Nuggets grabbed a 55-39 halftime lead by stifling Andrew Bynum down low and forcing Kobe Bryant to work harder for his baskets.
Bynum's putback with 1:18 left in the third quarter not only pulled the Lakers to 68-64 but his inadvertent elbow on the play broke Al Harrington's nose. He didn't return, but the Nuggets went on a 12-5 run to regain their composure and control of the game.
Bryant finished with 22 points on 7-of-23 shooting and Bynum had 18 points and 12 rebounds.
Kenneth Faried had 12 points and 15 rebounds as the Nuggets outrebounded the Lakers 55-44. Denver's bench outscored the Lakers' reserves 39-9.