PORTLAND, ORE., JUNE 12 -- The decision didn't take long. Two officials calmly overruled another one, and the Detroit Pistons found themselves one step away from an historic double instead of in the fight of their lives.

Officials Hugh Evans and Earl Strom said Danny Young's 40-footer at the buzzer didn't count. So the Pistons ran off the court with a most dramatic 112-109 victory over the Portland Trail Blazers and a 3-1 lead in the NBA Finals. No team has ever recovered from such a deficit to win the championship.

Young's shot came just a fraction of a second too late, and the Trail Blazers' furious fourth-quarter comeback had been for naught. They had come back from a 16-point deficit late in the third and in the fourth with a commitment to full-court pressure that rattled the usually calm Pistons.

"We were not prepared for their trap at all," said Isiah Thomas, spectacular again with 30 of his team-high 32 points in the second half. "And we did a terrible job. We knew that they would make a run and when they hit us with the trap, it was turnover after turnover after turnover."

"It was really disappointing," said Portland's Clyde Drexler, who was outstanding with a game-high 34 points and 10 assists. "We worked so hard with the trap to get back in the game. To get back and to take the lead and be right there and have a chance and let it slip through your fingers is really disappointing."

Of his 22 third-quarter points, Thomas scored 16 in a row, torching any Trail Blazer who came close enough to feel the heat. Joe Dumars, playing two days after the death of his father, scored 26 points. Vinnie Johnson added 20, as Detroit's three-guard rotation again bludgeoned Portland with 78 points.

Thomas "came out in the third quarter and demanded respect," Mark Aguirre said. "He showed us all."

Jerome Kersey scored 33 points and grabbed eight rebounds in a yeoman 45-minute effort for the Trail Blazers. He had 10 in the fourth, when Portland looked as if it would pull off one of the great comebacks in Finals history.

But Thomas returned to the fore just in time, after Drexler's free throws had given Portland a 107-106 lead ith 31.8 seconds left.

Thomas "was a very confident shooter from any distance," Detroit Coach Chuck Daly said. "He was penetrating and running the show. I think he got a little tired late. I think the trap bothered him. We just didn't advance the ball well. The court was open down court."

Portland had come all the way back, taking the lead after Mike Mathis overruled Jones and with 31.8 seconds left called Bill Laimbeer (12 points, 12 rebounds) for his sixth foul. Laimbeer and Drexler had gone running for the ball, off a missed free throw by Buck Williams (nine points, seven rebounds) with Detroit ahead by one. Jones had signaled the ball out of bounds to Detroit, but Mathis said no.

Detroit raved. The call stood, and Drexler hit both foul shots.

But Thomas's jumper with 25.7 seconds left gave Detroit a one-point lead. At the other end, he took the ball after Terry Porter crashed into Joe Dumars. It was the same kind of contact that had been called a foul in Game 2, and Portland cashed in for the win.

This time, it was no go. Neither player was put at an advantage because the ball was already loose. Vinnie Johnson took care of that by diving on the floor and tipping the ball to Thomas, who was fouled by Young with 8.6 seconds remaining.

Thomas made both free throws. Porter (17 points) was fouled at 6.5 seconds and made two shots to put Portland within one. But the Pistons broke the trap, and Gerald Henderson got a breakaway layin with 1.3 seconds left.

There was still time. Young was wide open from just inside midcourt, but he took one more dribble to get closer. It may have enabled him to make the shot, but it also made the shot too late.

"When it went in," Young said, "I thought they were going to count it. I thought Mathis was going to allow it, and then he went over to Hugh and Earl. I didn't know. I just tried to get as close as I could to the basket. And just hope."

Strom told a pool reporter: "By our mechanics, the lead referee {Strom} had the call on the final shot with the ball still in the man's hand when 0:00.0 was on the clock. The referees met to be sure all three had the same call."

"I thought they were going to discuss things," Laimbeer said. "Why the clock didn't start when the man touched the ball and whether the light went off . . . we kept waiting for the horn to go off. He kept dribbling."

It was unfortunate for Portland that it couldn't have played as well all game as it did in the final 12 minutes. But the Trail Blazers again fell asleep in the second quarter, even more perplexing since Thomas was on the bench for almost the last 10 minutes of the half after picking up his third foul.

The Trail Blazers scored 14 points in the quarter and a 10-point lead became a 51-46 halftime deficit.

"We were stagnant in the second period," Portland Coach Rick Adelman said. "And we just can't do that against a team like Detroit. We were just standing around and we played right into their hands."

Thomas was electric in the third. He hit four three-pointers, including three straight, and only a spurt in the final minute kept Portland within 83-73. He hit left of the key, right of the key, the top of the key. No shot was too daunting, and all found the net.

"I got some early fouls," he said, "and while I was sitting on the bench watching, I saw that we had the chance to really go after them and knock some wind out of them. So when I got in in the third quarter, I just wanted to take it to them and take it to them, and after I made my first few shots, I felt like I could make them from anywhere."

The Trail Blazers went to all-out pressure, trapping Detroit deep in the back court. The Pistons threw the ball away, or had to rush shots to beat the shot clock. Portland, led by Kersey, pounded the glass and got to the foul line by penetrating.

"We trapped them, really hurt them," Porter said. "We stayed on them. When we got to a point I thought we had them."

After Porter put the Trail Blazers ahead, 93-92, with 5:20 left, the game seesawed. Detroit got the upper hand, with Dumars and Thomas scoring 12 of 14 points in the crunch, and the Pistons led by 106-102 with 1:11 left. But Kersey made one of two to begin the final sequence.