Philadelphia 76ers Elton Brand (42) and Thaddeus Young (21) battle for the ball with the Chicago Bulls Luol Deng (9) and Carlos Boozer (5) during Game 4 of their NBA Eastern Conference quarter-final playoff basketball game in Philadelphia, Pennsylvania, May 6, 2012. [Photo/Agencies]
A victory on Tuesday in Chicago would give the 76ers their first playoff series win in nine years.
"I think we're confident," 76ers forward Elton Brand told reporters. "But we don't want to come back for Game Six. We want to finish this."
Spencer Hawes paced the 76ers with 22 points, making nine of 11 shots from the field.
Jrue Holiday added 20 after a sluggish start.
Chicago hung in for much of the game despite playing without injured center Joakim Noah and 2011 league most valuable player Derrick Rose, who was lost for the season earlier in the series. Noah has a sprained ankle.
"We had our chances," said Bulls forward Luol Deng. "We were right there and they were able to pull it out in the end."
The 76ers led by only a point when Holiday connected on consecutive three-pointers with 3:30 to play.
Chicago worked back to within two before free throws by Holiday and Andre Iguodala, who had 14 points and 12 rebounds, sealed the win.
Carlos Boozer led Chicago with 23 points and 11 rebounds.