Isiah Thomas scored eight of his 17 points in overtime as the Detroit Pistons beat the Boston Celtics 117-113 to advance to the Eastern Conference finals for the fifth consecutive year.

Joe Dumars led Detroit with 32 points, 25 in the first half, as the Pistons ousted the Celtics in six games of the best-of-7 series. Kevin McHale scored 34 points off the bench for the Celtics who overcame a 17-point third-quarter deficit, despite playing without center Robert Parish, who sat out with an ankle injury.The Pistons, attempting to become only the third team in history to win three straight NBA championships, will start the conference finals in Chicago on Sunday.

The game was tied 105-105 after regulation and Boston took a quick 109-105 lead on baskets by Reggie Lewis and Ed Pinckney.

But the Pistons chipped away. Thomas hit a bank 3-pointer as the shot clock ran out, then a short jumper with 1:41 remaining to put the Pistons ahead for good at 112-111.

Bill Laimbeer's basket gave Detroit a 114-111 lead, then Boston rookie Dee Brown was called for traveling. Moments later, Thomas hit a jumper over Brown from the left side for a five-point lead.

McHale scored Boston's last basket with 16 seconds remaining and Thomas, fouled by Brown, made a free throw with 14 seconds remaining for the final margin.

The other two three-peaters were the Minneapolis Lakers (1952-54) and the Celtics (1959-66).

Brown scored five points and Lewis capped a 7-2 burst that saw Boston cut Detroit's lead to 84-82 with 10:58 to play.

Two dunks by John Salley helped the Pistons push the lead back to 92-84 with 8:13 left, but the Celtics on several occasions closed within three.

Two free throws by Larry Bird gave the Celtics their first lead, 100-99, with 2:13 left in the fourth quarter.

The lead changed hands twice more, then Dumars tied it 103-103 with a basket with 1:22 left and James Edwards hit two free throws with 43 seconds left for a 105-103 Detroit lead.

Dumars, an 89 percent free throw shooter in the regular season, missed two with 21 seconds remaining. Lewis, who had 11 of his 23 points in the period, then tied it 105-105 on his own rebound with 7.8 seconds remaining.

Thomas' desperation turnaround from the free throw line at the regulation buzzer was short.

The Pistons led the entire first half. Boston missed its first six shots and trailed 7-0 before Brian Shaw finally scored 2:48 in.

Meanwhile, Dumars had the hot hand and the Pistons kept feeding him. Dumars, who made only 14 3-pointers in the regular season, made two in a row while scoring 10 consecutive points at one stretch.