AUBURN HILLS, Mich. _ The Boston Celtics showed why they have designs on reaching the NBA Finals.
And the Detroit Pistons' litany of miscues proved decisive in the 104-98 loss at the Palace on Sunday.
Isaiah Thomas scored 33 points and his Celtics (38-21) were able to beat back another late offensive surge from Kentavious Caldwell-Pope, who scored nine points in the fourth quarter to help the Pistons to a 96-95 lead with less than one minute remaining.
But Reggie Jackson launched an errant 3-pointer with 55 seconds left.
The Celtics' Al Horford grabbed the rebound, and on the ensuing possession rookie Jaylen Brown sank a corner 3-pointer while being fouled to give the Celtics a 98-96 lead with 37.1 seconds left.
He missed the free throw, but Smart grabbed the offensive rebound _ their fifth offensive rebound while Pistons center Andre Drummond was benched because of Boston's aggressive use of intentionally fouling Drummond, who was 1-for-11 from the line. The Pistons finished 16-for-35 from the line and committed 17 turnovers.
Smart made both free throws to give the Celtics a 100-96 lead with 37 seconds left.
Drummond finished with 17 points and 15 rebounds, and Jackson had 17 points and six assists. Caldwell-Pope led the Pistons with 18 points, and Marcus Morris scored 16 points.
The Celtics remain second in the Eastern Conference. The Pistons (28-31) fall to 7-4 in the month of February and still hold the eighth and final playoff spot in the Eastern Conference.
Pistons coach Stan Van Gundy got a quick time-out after the Celtics beat the Pistons down the floor for two easy layups to take an early 6-2 lead.
The Pistons' struggles continued with Brown, who scored seven points in the first quarter.
The Celtics took a couple of eight-point leads with the last coming at 19-11 on ex-Piston Amir Johnson's flying dunk on an offensive rebound.
Detroit cut the deficit to two at 19-17 on a Jon Leuer 3-pointer with 4:34 left in the first quarter.
The Pistons used a 9-2 run to take a 32-29 lead early in the second quarter.
But the Celtics answered with an 18-3 run to take a 47-35 lead at the 4:31 mark of the second quarter. Thomas accounted for five points, two assists and a steal during the run.
Jackson kept the Pistons around with eight points, including two 3-pointers, to close the half.
And after Horford missed a 3-pointer, Jackson gathered the long rebound and pushed it into the frontcourt.
He found Morris for an open 3-pointer from the wing to cut the halftime deficit to four at 54-50. Morris committed five turnovers in the first half.
The Celtics quickly pushed the lead to 67-52 open the second half, but Drummond's activity stabilized things.
His jump hook after an offensive rebound cut the deficit to 13.
Another jump hook cut the deficit to 11.
He then got a steal and went in for an easy breakaway, but he missed the dunk.
But he hustled back on defense and forced Johnson to travel.
Another hook shot cut the deficit to seven at 67-60.
Morris' three-point play at the end of the third quarter cut the deficit to 79-74.
