The soft and pock-marked grass of Court No. 2, historically one of the most notorious "upset courts" at the All England Lawn Tennis and Croquet Club, became the first-round graveyard of the Wimbledon title hopes of Arthur Ashe and Vitas Gerulaitis today.

Ashe, the 35-year-old champion of 1975 who thought he had a real chance of regaining the most prestigious championship in tennis, volleyed and returned serve miserably and was decisively beaten by Australian Chris Kachel, a recent refugee from satellite tournaments, 6-4, 7-6, 6-3.

Gerulaitis, who had dedicated an entire spring of hard work to "winning the big one, the only one I really care about," struggled from midafternoon to nightfall and finally lost to fellow 24-year-old American Pat DuPre, 7-6, 6-3, 3-6, 3-6, 6-3.

Those were the dramatic highlights - and most notable heartbreaks - of a wild opening day abbreviated by rain. Only 30 of 62 scheduled men's singles matches were completed and two were left unfinished overnight.

For the second consecutive year, defending champion Bjorn Borg got off to a jittery start in the curtain-raising match on Centre Court. He lost the first set was down 15-40 on his serve at 4-4 in the second, and was down a break at 4-5 in the third before squelching Tom Gorman, who played well except in the most pressurized moments, 3-6, 6-4, 7-5, 6-1.

Jimmy Connors, the champion of 1974 and runner-up to Borg the past two years, was leading Frenchman Jean Francois Caujolle, 6-2, 6-7, 7-5, 2-1, when play was suspended because of darkness on Court No. 1. Connors saved six set points in three different games in the second set, only to lose it in a tie breaker, 7-5.

Of the grand triumvirate of Borg, Connors and John McEnroe - from whom most observers expect the men's singles champion of Wimbledon's 102nd year to come - only McEnroe had an easy time today. He beat lesser American left-hander Terry Moor, 7-5, 6-1, 6-4.

Gerulaitis, seeded No. 4 behind Borg, McEnroe and Connors, was the man considered most likely to challenge the sport's current ruling troika and finally break into the rarefied company he has dubbed "The Two-Mile High Club."

For the Past two months, he had abstained from his celebrated playboy life style and put in untold hours of hard work, training and practicing under the guidance of his coach, Australian Fred Stolle.

Gerulaitis won the Italian Open on slow clay last month, but all along he said he was only slogging through Europe's most physically taxing tournaments with one goal in mind: Wimbledon.

Ever since he dethroned Ashe in the fourth round here in 1976, and took Borg to 8-6 in the fifth set of the most memorable match of Wimbledon's centenary in 1977, Gerulaitis has made Wimbledon his ultimate quest.

Last year he lost to Connors in the semifinals, but this year - after 10 days of five-hour-a-day practice sessions with Borg - he had high hopes.

They were all dashed today by DuPre, a 1976 Stanford graduate who admits candidly, "I consider myself a pretty horrendous grass-court player."

They ended at 8:47 p.m. on a damp and chilly evening, as a garbage truck collecting some of the refuse left behind by 29,142 hearty first-day spectators added to the commotion around Court No. 2.

No one knows exactly why Court No. 2 has been such a chamber of horrors over the years for men and women with lofty reputations and ambitions.

Perhaps it is the noise.Tucked away in the shadows of the high green walls of Wimbledon's more fabled twin arenas, next to the bustling main promenade that fronts the dozen outside courts, it gets not only the distractions of its own 1,625 spectators, but all the echoes from around the crowded grounds.

Perhaps it is the turf, which seems to get chopped up earlier than any other court, leading to an inordinate number of bad bounces.

As far as Gerulaitis was concerned, it was almost surely the heaviness of the conditions after intermittent drizzle had caused curtailment of play for some 90 minutes earlier in the day.

"His biggest asset is his speed, but the court and balls got so moist that they played extremely slow today," said DuPre, a bright and good-natured son of Belgian parents. He grew up in Birmingham, Ala., and now lives in La Jolla, Calif.

"Because the balls got so big and soft, he didn't have as much penetration as usual on his serve or volleys, and I was able to swing away and generate the pace," said DuPre, who is in the low 30s in the computerized world rankings of the Association of Tennis Professionals.

DuPre had beaten Gerulaitis a half-dozen times early in their junior and early professional careers, but had not played him since the summer of 1973.

Gerulaitis led, 5-3, in the first set, but then started experiencing the inconsistent forehand, erratic touch on the lob, and tendency to be timid on volleys and second serves that plagued him much of his nightmare day. He was squashed in the tie breaker, 7-2.

He was in trouble all the way in the second set, which was decided by one service break, to 3-1 in the heavy-footed but heavy-hitting DuPre's favor.

Then DuPre's serve went awry. "It just went down the tubes for two sets: I must have served 20 double faults," he said. And Gerulaitis seemed on the verge of finding the rhythm that Ashe never had on the same court.

But in the first game of the final set, a buzzing forehand cross-court passing shot by DuPre got him to 30-40 on Gerulaitis' serve. "Broadway Vitas," looking uncertain of himself, slapped his thigh in mounting despair.

He served again, but a big top-spin forehand return forced a backhand volley into the net. Gerulaitis turned, looked up at the roof of the players' team room in the distance - where a large throng, including his father, was watching his discomfort - and then walked, head down and disconsolate, to change over.

Gerulaitis had one chance to break back, at 30-all in the sixth game, but a backhand cross-court return clipped the net, hung in suspended animation, then fell back. A service winner to the backhand got DuPre safely to 4-2.

DuPre had a break point in the seventh game, held at 15, and then broke Gerulaitis for the match in an excruciating game that went to deuce four times. After a Gerulaitis double fault, a nice forehand cross-court pass got DuPre to mach point for the second time, and another off a deep volley to his backhand corner sealed the match.

"I was relieved, really relieved, that I didn't have to serve for the match," said DuPre, who jumped in the air and raised his arms in triumph at the end. "I've served for the match against a lot of good players and nothing ever came of it."

Ashe's demise was much more straightforward. He simply played horrendously against Kachel, ranked only No. 139 in the world, whom he had beaten easily in the first round of a tune-up tournament at London's Queen's Club two weeks ago.

Ashe led, 3-2, in the first set when the rains came, but never looked like he was in the match after it resumed. He muffed an embrassing number of forehands volleys, his old bugaboo, and also returned serve poorly - particularly off the backhand, his stronger side.

Kachel, who recently placed first in a five-week series of satellite tournaments in Australia and third in a similar series in Japan, had beaten Ashe once before, two years ago in Sydney.

"I played him the same way today. I concentrated mainly on his forehand. That's where all my passing shots went. And he always slices his serve to my forehand, which is my strength, so I was just sitting on it all the time," said Kachel-a once-promising junior whose fortunes had been so low in recent years that he spent 18 months working as a bank teller.

Ashe lost in the first round here last year to another Australian, Steve Docherty, but thought he was fit and ready this year to justify his No. 7 seeding and No. 8 computer ranking. But he never could get it together.

"I just didn't play well," he said, "He served well, returned well in spots, and got ahead in the tie breaker (3-0, Ashe having flubbed a forehand volley on the first point).

"I never did feel that I was close to finding the groove . . . I came in with very high expectations, I've been playing well, but today I just couldn't fire at all." CAPTION: Picture 1, Jimmy Connors slips to his knees in match against Jean Francois Caujolle in first-round match at Wimbledon. AP; Picture 2, John McEnroe uses his shirt as a hood during rain delay. UPI