EAST RUTHERFORD, N.J. — After a sleepless night, Rony Seikaly, the center of the Syracuse basketball team got up, got psyched up, thoroughly outplayed the very large Florida freshman who had made him too jumpy to sleep, and personally led Syracuse to a 87-81 victory Thursday night at the NCAA tournament's East Regional.

He felt a whole lot better.

Then he sat back, as a crowd of 19,552 at Brendan Byrne Arena did, and watched the second game of the night. That was a big mistake. What he saw was another very large freshman, this one from North Carolina, personally taking Notre Dame apart in a 74-68 win that carried Carolina into Saturday's regional championship game against Syracuse.

The poor guy might never sleep again.

What Carolina's J.R. Reid did could very well be the scariest thing to keep anybody awake since the killer who attacks people in their sleep in the "Nightmare on Elm Street" movies. Who did J.R. kill? The Fighting Irish. How did he kill them? By scoring 31 points, including 16 of the Tar Heels' last 17 points of the game.

Notre Dame, which trailed most of the night, rallied to get within three points late in the game, but Reid scored every Carolina basket in the last eight minutes--eight of them, including a runaway-train dunk with 27 seconds to play that made it 72-66 and buried Digger Phelps' guys for good.

The 6-foot-9, 240-pound Reid just turned 19 years old, but he is all man--"a man's body with a man's mind," teammate Kenny Smith called him--and he is the man Syracuse (29-6) must do something about if it is to get by North Carolina (32-3) and go to the Final Four for the first time since 1975.

The man who has to handle him, Seikaly, has been around. Born in Beirut and raised in Athens, Seikaly has grown up to be a hirsute, permanently 5 o'clock shadowed, 6-10, 240-pounder. At 21, he speaks better English and plays better basketball than he did when he first came to America, but he still can do better on both counts.

Seikaly--pronounced "cycle-lee"--scored a career-high 33 points Thursday, far better than his average of 14 per game.

"It was my most tasteful game yet," he said later, meaning it was sweet.

Although Florida sank 10 three-point shots to Syracuse's none, and although the Gators' bench outscored the Orangemen's bench by 29-0, Seikaly's manhandling of Florida's center gave Coach Jim Boeheim's team what it needed to reach the regional final for the fifth straight year. Florida, in NCAA play for the first time, finished the season 23-11.

Seikaly made the swaggering 7-2, 245-pound Florida freshman Dwayne Schintzius eat a lot of pre-game words. After a lot of talk about how good he was--some of that talk from himself--all Schintzius could do was score six points and foul out.

Alleged to be good enough to be the 1988 U.S. Olympic center, Schintzius shot airballs from five feet from the basket, and was victimized by a number of alley-oop passes, in complete defiance of his size.

"I thought I was God's gift, but I wasn't," the duck-tailed, downhearted teen-ager said afterward.

Said Seikaly, in an accent part Greek and part New York: "What one guy can say in the paper can't beat us. It did keep me up last night, and it kept me on the edge of my seat this morning. I couldn't wait to get to the game."

Seikaly came to the game so charged up he had 23 of his points and 7 rebounds by halftime, staking Syracuse to a 40-33 lead. He dunked repeatedly over Schintzius, most of them by Sherman Douglas, who finished the game with 10 assists.

It was obvious Syracuse wanted to stick it to the freshman, who had never insulted the Orangemen personally but had boastfully compared himself to Pervis Ellison, the player who as a freshman led Louisville to the 1986 national championship.

Florida Coach Norm Sloan said of his center after Thursday's loss: "He still doesn't understand how the remarks you make can be interpreted. He did everything he could to psyche Seikaly up, to let himself in for a long, long night."

Everyone in Syracuse's starting lineup scored in double figures, and no one else on the squad took a shot. Florida, on the other hand, got only nine points out of its starting front line, and needed home runs by the "M & M Boys," guards Vernon Maxwell and Andrew Moten, from the three-point range to stay in the game.

Florida fired up 22 three-point attempts in the game, Syracuse only four.

Behind Maxwell, who came back from a terrible first half to score 20 of his 25 points in the second, Florida rallied to take the lead, four minutes into the second half. With a little more than five minutes to play, the Gators even got in front by five, and had Syracuse in serious trouble.

Then came the play that changed the game--a play made by a freshman, but not Schintzius.