"Broadway Vitas" Gerulaitis gave a one-man command performance yesterday, more solid than spectacular, and quickly brought the curtain down on Eddie Dibbs, 6-3, 6-2, 6-1, in the title match of the World Championship Tennis (WCT) Finals.

The flamboyant 23-year-old New Yorker served well, volleyed with exceptional facility and touch, and even outplayed the usually tenacious Dibbs from the backcourt. In fact, Gerulaitis did just about everything but sing and dance, to the growing applause of a crowd of 9,128at Moody Coliseum.

His father, Vitas Sr., a one-time Lithuanian Davis Cup player who taught him the game, and former Australian Davis Cup Captain Harry Hopman, who coached him as a teen-ager at Port Washington, N.Y., watched as Gerulaitis captured his third important title of the past 12 months.

For adding the WCT crown to the Italian and Australian Open titles he won in 1977, Gerulaitis collected $100,000 and use of a Cadillac for a year. That seemed a bit of automotive over-kill for the reigning bon vivant of tennis, who already owns two Rolls-Royces, Porsche, and is awauting delivery of a custom Ferrari.

This was the first time in the eight years of this prestigious final playoff for the top eight finishers in a series of WCT-promoted tournaments that the title was decided in straight sets. Gerulaitis needed only 1 hour 35 minutes to add his name to those of previous winners inscribed on the gleaming gold championship trophy: Ken Rosewall (1971-72), Stan Smith, John Newcombe, Arthur Ashe, Bjorn Borg and Jimmy Connors.STGerulaitis was briefly shaky at the start of the match, but grew increasingly 6 confident in both his shotmaking and his swift choreography around the medium-slow syntheic carpet.

By the end he was anticipating superbly, diagnosing Dibbs' every move before he made it, and hitting passing shots and volleys alike with the clean precision of a skilled surgeon's incision.

Gerulaitis lost his serve only once, in the first game muffing two easy volley around the first of his three double fwaults. Dibbs then held his serve, witn the aid of three Gerulaitis errors, after two unforced errors had put him at 0-30.

Thereafter Gerulaitis purged the mistakes from his game, while Dibbs continued to be surprisingly flat and ragged.

Gerulaitis broke at 15 to get back-to 2-2, threading the needle with a forehand down-the-line pass off a low backhand down-the-line volley after drawing Dibbs in with a sharply-angled backhand cross-court chip.

"The guy was all over me. After 2-0 in the first, I was never in it," said Dibbs, 27, who like Gerulaitis was born in Brooklyn but then grew up hustling matches on the public courts of North Miami.

The scrappy, 5-foot-7, 160-pound hustler had beaten Ilie Nastase and Corrado Barezzutti in straight sets enroute to the final.

Dibbs collected $40,000.

Dibbs usually prefers to stay in the backcourt, thumping the deep, topspin ground strokes that he hits unorthodoxly, but with great pace and accuracy. Gerulaitis took away his passing shot, though, intercepting many with agile volleys, and ultimately made Dibbs try to attack. The Floridian was no match for him at the net.

Gerulaitis, who beat Raul Ramirez in the first round and advanced by default when favored Bjorn Borg withdrew with an infected right thumb, was sharp despite his three-day layoff.

Dibbs had beaten Gerulaitis in all four of their previous meetings, but only one was within the past year, after Gerulaitis ascended to the upper echelon of the world class. "Three years ago I wasn't a tennis player," said the lithe, 6-foot, 160-pounder, now ranked fourth best in the world.

Gerulaitis does not hit particularly penetrating volleys, but he missed very few. He opened up the court smartly, varying the pace, direction and angle of his approach shots and then came dancing in for the point-ending thrusts, including some lovely drop and acutely-angled volleys.

Gerulaitis has been working on his second serve with Australian Fred Stolle, coach of his New York Apples in World Team Tennis, hitting it harder and deeper. That is a gamble - he served 14 double faults against Ramirez - but a calculated one because he gets successfully to the net behind it so often.

Yesterday he won the bet. Dibbs did not get any short second serves to punish, the way he did against Barazzutti. He had hoped to blast some returns for outright winners, or get in behind them for easy volleys, but Gerulaitis wouldn't let him.