Third-placed Lazio could have cut Juve's then five-point lead to two in Saturday's earlier game, but lost 1-0 to midtable Chievo to stay below Napoli on goal difference.
After missing six of their initial seven shots in the second half, the Celtics relied on Pierce driving to the basket where he converted a three-point play and was fouled, hitting five free throws that cut it to 70-62.
Dredge has only enjoyed one top-10 finish this year and was resigned to making it four missed cuts out of five until the weather turned and the cut-off point dropped to two over, keeping him here.