With never a worry, Jimmy Connors buried John McEnroe, 6-3, 6-4, today in a semifinal match of the $300,000 Pepsi-Cola Grand Slam of Tennis. Aggressive and powerful as always, Connors ended for the moment any imagining that McEnroe, the Davis Cup star at 19, had passed by the old man, now 26.

"The pressure... "McEnroe said, speaking of Connors' relentless assault. "Well, I'm just not used to standing five feet behind the baseline and trying to hit winners all day."

What McEnroe does best is smite a serve and then follow it for a killing volley off the poor victim's pitiable return.Against Connors, no mere mortal today, McEnroe's game was useless, for Connors returns serve better than anyone.

How fitting it was that the 75-minute match in glorious sunshine and a brisk breeze toward the ocean ended with Connors winding up that twobanded backhand for a roaring cross-court winner off a McEnroe serve that would have ripped the racket out of a layman's hand.

McEnroe could only stand and watch, helpless in the face of greatness, and afterward he said how it was an honor to be in this tournament matching winners of the sport's four major championships. "Anytime I play Jimmy, whether I win or lose, it's good because I am learning," McEnroe said. "The same with Bjorn, too."

Bjorn Borg, who with Connors is at a level of the game a head above the crowd, plays a Saturday semifinal against Guillermo Vilas. The winner meets Connors for a $150,000 prize Sunday afternoon.

As strong as Connors was today, the ease of his victory was created with McEnroe's generous help, for the youngster never played well when it mattered most.

One example is vivid: Leading 40-30, on his serve with the first set at 3-3, McEnroe lost the next three points to throw away that game -- and he promptly lost the next two games, also, although he had game points in each.

"I don't think I played badly," McEnroe said, adding the unnecessary confession, "I just didn't win the big points."

Connors' determination on important points is palpable, made as real as a rock by his cock-o'-the-walk strut, and he brought out the swagger in celebration when another long rally ended with McEnroe, impatient with all this hitting to and fro, trying a rifle-shot forehand that went too deep.

That point gave Connors the advantage in the game that would put him up, 5-3, in the first set, and he finished it with an untouchable overhead off a sorry McEnroe lob.

The last game of the set went to deuce four times before McEnroe botched a backhand and followed that with a double fault.

Four times in the first set, McEnroe needed only one more point to win a game but could not get it against the man he has lost to five times in six tries. Only last month, when Connors quit in mid-match with a bleeding blister under his toe, has McEnroe beaten him.

The important points belonged to Connors in the second set, too. With the games, 4-4, McEnroe needed a single point to break Connors' serve for the second straight time. The capacity crowd of 10,000 sensed a comeback. They ignored history.

Connors promptly won the next two points off his first serves and, after two deuce points, finished the game by forcing McEnroe into mistakes.

"The momentum had been going his way," Connors said. "And then I had it back. I was pumped up at 5-4."

Connors was so pumped up that McEnroe, serving to stay alive, won only one point in the match-ending game.