In a madcap scene unprecedented even for the Italian Open, most hysterical of the world's major tennis championships, hometown idol Adriano Panatta advanced yesterday to the final when first the British umpire and then Panatta's opponent, Jose Higueras of Spain, walked off court in protest, prematurely ending a match that had fallen to mob rule.

Panatta will play top seed Bjorn Borg, a 6-4, 6-3, 6-0 victor over Eddie Dibbs in an earlier semfinal, for the championship today. But the Felliniesque match that Higueras quit in disgust after losing the second set 5-7, having blow a 6-0, 5-1 lead and six set points, could have long-term repercussions.

"If the Italian public wants a tournament in which only Italians can win, they're going in the right direction," said David Gray, general secretary of the International Tennis Federation, profoundly disturbed the spectacle he witnessed at Foro Italico. "If this type of outrageous crowd behavior persists, eventually only Italians will play here and the tournament will cease to be important."

Higueras, 25, a normally placid clay court specialist who seemed destined to be in the biggest final of his ascending career, was the first to say he would not return to Rome.

"I will never play in Italy again - tournaments, Davis Cup, anything. I am finished with this place," he said. "It was not Adriano's fault, but the crowd's. They called me everything from an idiot to 'son of a whore.'"

Even though he was largely responsible for bringing pandemonium down on himself, pointedly protesting a couple of minor injustices when he was winning easily and later making a scornful obscene gesture that incited the full fury of the volatile Italian spectators, Higueras undoubtedly will have a selective memory about this wildest of episodes in the white marble passion pit that is Foro Italico's "campo centrale."

He will recall the soft drink can and the coin hurled at him from the stands, the latter while play was in progress, a couple of questionable "let" calls on his best serves, and fans standing and angrily shaking their fists on him, screaming obscenities, rhythmically chanting "scemo" (fool) and "buffone" (buffoon).

And he will remember Referee Sergio Baruti overruling chair umpire Bertie Bowron who tried to give Higueras two serves after whistling, shouting and other distractions interrupted play following the spaniard's errant first serve.

Bowron, a retired British Foreign Office employe who has umpired in the Italian championships for 14 years, was specifically requested by Panatta to officiate his matches because of his reputation for unflinching neutrality and rapport with the raucous crowd.

Bowron was so startled that Baruti did not back up his effort to give justice to Higueras despite the intimidating crowd, and left the court two points before the Spaniard did.

"I wasn't trying to be a hero. I was just making the point that the referee had no authority to overrule my decision," said Bowron.

He was cheered by the crowd as he scurried off, doffing his hat and waving to them, but afterwards said.

"This was absolutly the worst incident I've ever seen here. The crowd gets so excited they get out of control. The Romans are wonderful, exuberant people, but they want Panatta to win at any cost."

Panatta, 27, was embarassed and apologetic two years ago when a linesman's larceny and the extremism of the crowd infuriated Harold Solomon into walking off - thinking he had been disqualified - when two points away from victory in a tight quarterfinal match.

Panatta went on to win the title over Guillermo Vilas, and took the French Open two weeks later, sweeping the two most important clay court events of the continent.

This time the handsome and charismatic son of a Rome tennis club maintenance man was not so sympathetic. "If I was playing in Spain, the same thing would happne to me," Panatta said, remembering that he was taunted and attacked with pillows after playing indifferently in a Davis Cup Match last year in Barcelona.

"I tried to quiet the crowd down, but it was impossible," Panatta added. "Jose stirred them up by arguing and then he got flustered. He should know better." Indeed he should , for this is a way of life in Latin countries, where tennis crowds emulate those at emotional soccer games.

Panatta started abysmally, winning only 13 points in nine games as the steady, stylish Higueras surged to a 6-0, 3-0 lead.

Higueras was playing beautifully, with touch and pace on the flowing ground strokes he hits with a big backswing and a great flourish of a follow-through.

Panatta, meanwhile, was as dreadful as he had been in his first-round match against defending champion Vitas Gerulaitis, when he won only four points in the first games before comingback to win, 7-6, 7-5.

The sellout crowd of 9,000 was subdued and silent, stunned by their heros ineptitude. The biggest cheer, ironically, was for Higueras when he insisted that a point be replayed after a bad call against panatta in the eighth game.

Higueras lost his serve at 3-0, but promptly broke again and had the first of his six set points when Panatta double-faulted and overhit a forehand approach to fall behind, 1-5, 15-40.

But Panatta, an attacking player whose flamboyant game is built on taking risks, is a tough character in tense situations, with set or match point against him.

Playing bodily and better, he saved three set points in the seventh game, two from 40-15 on Higueras' serve in the next game (Higueras lost his serve finally on a double fault), then held at love to 4-5.

The crowd came alive with Panatta's revival, cheering and chanting "Dai, Adriano" (come on, let's go). Higueras was getting nervous, and he strated to blow his cool at 30-all in the next game, serving for the set for the second time.

A policeman walked across the court, behind Higueras, just as he was about the serve. There was a brief delay. Several spectators whistled just as the Spaniard got ready to serve again. But instead of ignoring the distractions, Higueras threw the two balls in his hand defiantly back at a ballboy, and walked over to complain to Referee Baruti.

This merely agitated the crowd, which became so animated that it took half an hour to finish what turned out to be the pivotal game.

Higueras saved one break point with a good serve and backhand volley, and got to advantage: his sixth set point. But here he complained to Umpire Bowroom about spectators making noise as he delivered his second serve, derisive chants poured down on him.

Higueras, his concentration now gone, made two unforced errors, giving Panatta the advantage. As cheers reverberated through the arena, the Spaniard turned and gave the crowd what one Italian described as "the coarsest gesture we have in Europe." Now the full wrath of an excitable people tumbled down on him.

It was here that the Coca-Cola can was thrown. Higueras picked it up and indignantly carried it to Baruti.

Mario Belardinelli, the Italian National coach and Panatta's mentor, grabbed a microphone. "Please listen to me a minute," he said, "Please let the players carry on with the match."

That might have been a soothing voice of reason, but he added: ". . . even if one of them has made a nasty gesture." These words fueled the crowd's ire. They stared heckling Higueras anew.

The beleaguered Spaniard won a point to get back to deuce, but Panatta got to advantage on a net cord winner. Higueras was livid. He picked up a coin and gestured to Baruti that it had been thrown during the rally. The referee strode out on the court to see for himself, a TV man behind him, microphone in hand.

Higueras netted e longest and ugliest games in tennis history. Panatta he longest and ugliest games in tennis history. Panatta held serve at 15 to lead, 6-5, and Higueras looked as if he wanted to quit. Jose Manuel Couder, the Spanish Davis Cup captain, talked him into carrying on.

Higueras got to 40-30 in the 12th game, but a backhand long and a volley error put Pannatta at set point for the first time. Higueras served a fault, but after prolonged hooting, Bowron awarded him two serves. Now the crowd thought Panatta was being robbed, and expressed its displeasure with more commotion.

Panatta got to advantage again, Higueras saved another set point, and then, Bowron repeated his fully justified decision. This time Baruti overruled him. "The referee says 'Only one ball,' so I'm coming down. This is not right," Bowron announced to the crowd, and he hopped out of his high chair and scurried off. The TV commentator was right there to interview him.

A new umpire installed, Panatta won two points to take the set, and this time Couder could not talk Higueras out of quitting. Officially the score was Panatta, 0-6, 7-5, retired, but that bald line in the record book can never tell the story of this tempestuous afternoon in Rome.