When Adriano Panatta's last errant backhand plunked forlornly into the net late Wednesday afternoon, concluding the local hero's second-round loss to Floridian Brian Gottfried in the Italian Open Tennis Championships, a leading Italian tennis writer, Rino Tommasi, shrugged in dejection.

"The tournament is finished. Finito," he sighed unhappily. "Tonight, they should take down the nets. The fun is over."

Actually, there are three days left in this annual Roman circus of sport, a $200,000 tournament that is second in prestige only to the upcoming French Open on the continent, where tennis is played on slow, red-clay courts and picturesque and colorful surroundings.

Funny things can happen at Foro Italico, the grandiose playpen that Mussolini built in the 1930s so the banks of the Tiber, overlooked by the emerald hills and elegant houses of the fashionable Monte Mario section of Rome. This is especially true when there is an Italian left at the quarter-final stage of the tournament, as there is this year: grim-faced Corrado Barazzutti, known to his countrymen as "Soldatino" meaning "Little Soldier."

Traditionally the Italian is the sport's most tempestuous major championship, enlivened almost inevitably by controversies, unexpected or bizarre twists, and a peculiarly Roman passion for raucous crowd participation and disorder on the court.

The most memorable madness always occurs when a native son -- usually, the gifted and charismatic Pannata -- is locked in close combat with a foreigner on Foro Italico's Campo Centrale, the center court surrounded by a white marble echo chamber of an arena.

The 9,000 voluble Italians frequently conspire to lift a native player to dizzy heights, supplementing his individual initiative with noisy partisan ship that both inspires him and intimidates opponents and officials. Oftentimes, patriotic linesman are provoked into helping out with outrageous hometown calls.

This year, Panatta went out rather meekly -- never getting into the match against Gottfried enough to stir up some help from his friends. But just when it seemed that there would be no Italians in the quarterfinals for the first time since 1975, Barazutti rallied today to beat favored Chilean Hans Gildemeister, 4-6, 6-4, 6-3. Gildemeister did not try on the last three points of the match, after the crowd taunted him with ear-splitting chants of "Scemo" (Stupid) and "Buffonic" (Fool) for disputing a linesman's decision.

Gildemeister brought this cacophony on himself, arguing what appeared to be a correct call.He had complained earlier about noise, and grumbled sourly -- a silly thing to do at Foro Italico. He should have known better. Nevertheless, the indignant insults he encoutered warmed the hearts of observers who had judged Rome to tame -- even dull -- so far this year.

"People were beginning to say the tournament had lost its character: no blood, no throwing things on the court, no trying to kill the players.But today, the Romans restored their honor. The Colosseum returned to the Foro," crowed Gianni Clerici, the flamboyant columnist for Il Giorno in Milan, a patrician for Lombardy who dismisses Romans and all other southern Italians as "uncultivated . . . mafiosi."

Today's attempt at pandemonium was mild by local standards, however. There will be opportunies for more authentic bedlam when Barazzutti plays Frenchman Yannick Noah Friday, the winner to face the Manuel Orantes-Tomas Smid victor in the semifinals. In the other half of the drew, top-seeded Guillermo Vilas plays Raul Ramirez, and the lone American survivor, Eliot Ttltscher, opposes Ivan Lendl, who today beat Gottfried, 6-4, 6-4.

Still, the heart and much of the soul went out of this tournament Wednesday when Panatta, the champion here in 1976 and runner-up in 1978, was dispatched ingloriously by Gottfried, 6-2, 6-3.

No more, for this year at least, will the marble slabs and metal super-structure of the Campo Centrale reverberate with rhythmic chants of

"Ah-dree-ah-no, clap-clap-clap-clap-clap . . . Ah-dree-ah-no, clap-clap, clap-clap-clap."

At age 29, Panatta is seldom the player these days that he was in 1976, when he swept the gruelling Italian and French opens back-to-back to establish himself firmly among the world's top 10 players.

He is presently ranked only 45th in the world, but remains capable of producing some sublime tennis in Italy, where the clay and the adoring masses uplift him. He played superbly last week to win a $50,000 Grand Prix tournament in Florence. This boded well for Rome, even though he was well for Rome, even though he was not seeded here.

In the hearts and minds of his countrymen, Panatta is still the noblest Roman of them all. Sloe-eyed and handsome, the son of a former caretaker at a local tennis club, he is vastly more popular than the dour and ferret-faced Barazzutti, a less-stylish player and personality from Udine, in the nothern provinces.

"In Italy, Panatta is tennis. He is the one everbody cares about, bets on, lives and dies with. He attracts the big TV following and puts tennis on the front page of the newspapers," said Tommasi.

The mournful effect of his early defeat here was most noticeably reflected in the long faces of officials hoping for weekend sellouts and other merchant of tennis with a financial stake in the tournament.

"It hurts very much the whole tournament," said Cino Marchese, consultant to one of the numerous Italian tennis clothiers, and Panatta's business manager.

Marchese went into the players dressing room, overlooking the five outside courts at Foro Italico, all submerged in an enormous horseshoe crater ringed by stone bleachers and tall, parasol pines with climbing rose bushes girdling their trunks. He extended his hand to Gottfried, who was munching a ham and cheese sandwich before his doubles match.

"Congratulations Brian. You played very well," Marchese said.

Then, in a stage whisper: "You sonofabitch."

Gottfried -- who is unfailingly eventempered and blandly gracious -- just grinned. He knows that in Italy, the man who beats Panatta is a spoilsport in a league with the The Grinch Who stole Christmas. He didn't mind. Rome has been good to him, and he is well known here, having won the doubles title a record four consecutive years (1974-77) with Raul Ramirez.

"I figure I gave them a present seven years ago, my first time over here," Gottfreid said, recalling his introduction to Roman tennis in 1973. He had a first-round bye, then played his opening match on the Campo Centrale against Ezio di Matteo, a street kid from Rome with modest skills but massive heart.

Di Matteo was a typical continental roadrunner, bred on slow clay and heavy, pressureless tennis balls. He roamed the baseline, pushing back an endless barrage of looping ground strokes, but was tough when he had red dust between his toes and chants of "E-zi-o" and "I-tal-ia" pounding on his eardrums. He teased the inexperienced, net-rushing Gottfried to an ignominious, 6-2, 6-3 defeat.

Gottfried recalled his misgivings. "I didn't know what in the world I was going to do out there. I had read and heard all these stories about playing an Italian in Rome, and how they got all the close calls and stuff," he reminisced. "Pretty soon, you start imagining that your shots are hitting the lines when they're actually a couple of inches out. I didn't know whether to question them or keep my mouth shut. I was totally confused. I ended up not saying anything, just smiling the whole match and winning only five games. Naturally, the Italians loved me."

By coincidence, Gottfried never again played an Italian in singles here until he vanquished Panatta Wednesday. "I've always enjoyed coming back here, because it's such a colorful place, and I could never understand why a lot of players refused to come to Rome," he said afterward. "Then I realized it was I hadn't played an Italian here since di Matteo that first year."

He was present for some of the most ritous episodes of recent years, however. He saw the crowd almost steal a semifinal match from Ilie Nastase on behalf of Paolo Bertolucci, the stubby "Pasta Kid," in 1973, when Nastase had to duck a bottle thrown from the stands. He saw his friend, Harold Solomon, quit a quarterfinal match against Panatta in anger and disgust after a crucial third-set call was blatantly stolen by a linesman.

And he witnessed perhaps the most madcap scene of all, in 1978, when Panatta came back from an 0-6, 1-5 deficit saved by six points, and ultimately was awarded a semifinal victory when first the British umpire, then opponent Jose Higueras, walked off the court to protest what had degeneration into mob rule by 9,000 impassioned Italians.

On that occasion, Higueras foolishly protested a couple of modestly questionable calls when he was winning easily, then made an obscene gesture that brought a flood of verbal abuse down upon him. "They called me everything from 'idiot' to 'son of a whore,' said the Spaniard, who unfortunately understands Italian. He was subsequently swamped in hoots and whistles, and had to dodge soft drink cans and coins hurled from the stands.

Through it all, a zealous local TV sportscaster ran on court, trying to interview the principals in mid-pandemonium.

It was this wretched excess -- combining the quintessential Roman tennis ingredients of nationalism, hero worship, passion play, vigilante justice and theater of the absurd -- that brought about reforms, starting last year.

Each ticket sold now bears "rules of behavior" for spectators, including admonitions to be "honest" in judging line calls and to refrain from applauding "a mistake by the opponent" -- presumably meaning any non-Italian, Surprisingly, most of the audience seems to have taken these guidelines to heart. Spectators police each other. Moreover, globetrotting "Grand Prix supervisors" -- neutral super-arbiter of all on-court disputes -- are on the job in Rome.

Still, it is not certain how effective the rules or supervisors would have been had Panatta not been hopelessly out of his match. Down triple match point on Gottfried's serve at 5-3 in the second set, a few of his countrymen were intent on reviving him, screaming and making bird and animal noises as Gottfried tossed the ball up to serve. "You start to think more about what they're going to do than about where you want to serve," said Gottfried, "But I just decided to block it all out, crack the serve, and hope it went in." It did.

Such strength of character in the face of local boisterousness is one of the many charms of the Italian Open, Along with the lovely grounds, the beautiful women, the food and wine, the statues and the engaging vendors intent on cheating foreign visitors.

It is all part of the inimitable scene that is Roman tennis. Unfortunately, it is not nearly as much fun with Panatta gone.