Jimmy Connors has long found Spaniard Manuel Orantes a troublesome opponent, and meeting him for the first time in his natural habitat - slow, red European clay - might have been a bit like trying to seek out and destroy Br'er Rabbit in the briar patch.

But just when Connors appeared to be running into a thicket of trouble today on the damp center court of Stade Roland Garros, he turned both foxy and ferocious and devoured Br'er Orantes to reach the quarterfinals of the French Open tennis championships.

Connors lost a thorny first set and was down three break points in the first game of the second, lucky to escape that peril when Orantes butchered an easy overhead smash two yards beyond the baseline.

Thus reprieved, Connors ran seven straight games from 1-1 in the second, slugging shots explosive enough to defoliate any briar patch. He not only caught Orantes, but left him drawn, quartered and naked as a skinned rabbit, 4-6, 6-1, 6-3, 6-1.

Connors, seeded second to defending champion Bjorn Borg in the world's premier clay court championship, next will play his American compatriot and contemporary, Eddie Dibbs.

Dibbs was fortunate to survive the day's opening center court match against Wojtek Fibak of Poland, 4-6, 6-4, 6-1, 1-6, 6-4.

Fibak led by a set and 4-3, with a service break in the second and three in the final set. But he could not stand prosperity.

Victor Pecci, the 6-foot-3 "Leaning Tower of Paraguay," fell with all his weight on Harold Solomon, toppling the little native of Silver Spring, Md., 6-1, 6-4, 6-3.

Pecci, who in the previous round had upset Corrado Barazzutti of Italy in straight sets, except his quarterfinal opponent to be the 1977 champion and 1978 runner-up, Guillermo Vilas.

But the Argentinian left-hander, seeded third, found himself in dire trouble at nightfall. He trails Gene Mayer, the ascending American who defaulted to him in the semifinals of the Italian Open because of the after-effects of severe cramps, 5-7, 6-1, 7-6, in a match suspended overnight by darkness.

Vilas was twice up a break in the thrid set, and served for it once, but Mayer broke him back with a splendidly varied attack of drop shots, lobs, volleys and the well-disguised ground-strokes that he hits two-fisted from both sides. He went on to win the best-of-12-point tie breaker, 7-5, to assure Vilas a restless night.

Also reaching the quarterfinals today - joining Borg, Vilas Gerulaitis and Hans Gildemeister, who advanced Sunday - was Spaniard Jose Higueras. He led Californian Eliot Teltsche by 6-3, 6-4, 3-2 when a thundershower inundated the center court and forced suspension of their match Sunday evening.

This morning, they resumed on court No. 2 - moved, apparently, because the tedium of their endless, defensive rallies had driven spectators away in droves. In relative privacy, Teltscher made a spirited comeback to level at two sets all, but Higueras, awakening after his siesta, choked off the uprising, 6-3, 6-4, 3-6, 1-6, 6-3.

In the women's singles, Chris Evert advanced to the semifinals by thrashing erratic Ruta Gerulaitis, who was rather intimidated by her first appearance in the steeply banked stadium, 6-0, 6-4.

Evert's next opponent will be Australian Dianne Fromholtz, who was sharp and aggressive in overwhelming Virginia Ruzici, 6-0, 6-4. The Romanian won the title here last year, when most of the top women were playing World Team Tennis in the United States.

Connors versus Orantes matched two contrasting left-handers - a slugger and a counter-puncher - late in the afternoon of a gray, melancholy day that was just starting to turn breezy and chilly.

Connors had won nine of their 12 previous meetings, but Orantes had captured a couple of memorable ones on clay: the final of the 1975 U.S. OPEN AND THE 1977 U.S. Clay Courts. Moreover, the heavy conditions today figured to suit his soft, gossamer game.

He broke Connors' serve in a long first game and led, 3-1, but Connors broke back and went ahead, 4-3. Then Oantes stopped trying to punch with Connors, a game he could not possibly win, and started taking pace off the ball. He moved Connors around, hitting soft and short, and won eight straight points, six on balls that Connors overhit.

Orantes was serving well and playing confidently at this point. When he is "on," the elegant Spaniard is an artist at work, his ground strokes flowing and delicate, his footwork as nimble as a great dancer's, his tactics an intricate tapestry weaved out of the whole court.

But he started to go awry when he let Connors escape those three break points in the first game of the second set. First he nettled a return of serve, then a backhand cross-court passing shot so close that he fell to his knees in a prayerful pose when it clipped the tape, and finally an easy smash from mid-court, after he had wrong-footed Connors.

Orantes put on a sleevless pullover after that game to protect himself from the increasingly nippy breeze.But it proved to be a wind that blew no good to him. His legs seemed to stiffen, his energy to dwindle, his ground strokes to erode, as the temperature dropped. He continued to try to coax the ball, but it no longer sponded to his touch.

Connors, meanwhile, was starting to boil. Time and again he put away devastating overhead smashed with animalistic grunts that made the Parisian audience gasp. He took charge and figuratively beat Orantes to a pulp.

"At the beginning, I was maybe a little impatient, trying to go for too big a shot when Manolo wasn't giving me anything to hit," Connors said. "Then I got a little more patient and kept the ball in play until I could hit a big shot."

Orantes, smiling in defeat because it was a good-natured match, with lots of by-play and pantomime from both men, concurred.

"It's difficult to keep making good shots when you are all the time running, running, and under such pressure," he said.

Solomon, the runner-up here in 1976, might have said the same, for Pecci gave him no quarter - serving oppressively and hitting his big goround strokes deep until he forced an error or hammered his way to the net for a killing volley or smash.

Pecci won the last four games of the second set and swarmed to 5-2 in the third, never really giving Solomon another chance to get his teeth into the match, the way he had after losing the first two sets to Stan Smith on Saturday. CAPTION: Picture, Chris Evert backhands a two-hander at Ruta Gerulaitis. AP