The spirit of a sun-filled day at Wimbledon was summed up nicely by a mustachioed Englishman with a pink rose in his lapel who looked heavenward and commented: "We picked today to have our summer."

On the fifth day of the world's premier tennis championships, the somber gray clouds moved on. Eighteen grass courts bustled with activity from noon to nightfall, and 34,434 spectators shed their overcoats, put away their umbrellas and remembered what a joyous and thrilling spectacle Wimbledon can be.

The referee did his best to reduce the backlog of approximately 100 matches caused by the showers of previous days, and two of the best unfolded simultaneously, side by side. On soft and unpredictable court No. 3, No. 2 seed John McEnroe came within three points of defeat before beating Australian Terry Rocavert, 4-6, 7-5, 6-7, 7-6, 6-3.

Next door on No. 2 -- the "jinx court" where McEnroe and three other seeds were rudely uprooted last year -- Pam Shriver served poorly but gutted out a torturous 6-3, 1-6, 9-7 victory over the No. 16 seed in the women's singles, left hander Sylvia Hanika of West Germany.

At the same time, Bjorn Borg was winning his 30th consecutive singles match at Wimbledon on Court 1 over Shlomo Glickstein of Israel, 6-3, 6-1, 7-5. The 22-year-old Glickstein, admittedly a bit awed at first by the surroundings and his opponent, played well in the third set and gave the four-time champion a tougher sparring session than anyone had anticipated.

Earlier on the same court, Ilie Nastase played with grace and masterful touch, and was impeccably behaved, in completing a 4-6, 6-2, 5-7, 6-2, 6-2 triumph over Dick Stockton in a match that had been suspended overnight.

On his way back to the dressing room, however, the mercurial Nastase took a poke at a reporter from the London Daily Mail, who he apparently felt was prying into the recent breakup of Nastase's marriage, a story that has captivated the front pages of the sensational British tabloids. Nastase knocked off and broke the man's glasses, then said later that he would "talk only about tennis."

During the course of the afternoon, a wanderer could see Vitas Gerulaitis dropping a first-set tie breaker before beating Sashi Menon on Court 3, and Roscoe Tanner closing out a carried-over match against Aussie John Fitzgerald in a fourth-set tie breaker on Court 14.

Martina Navratilova, the 1978-79 women's champion, begrudged only two games to Floridian Rayne Fox, and No. 2 seed Tracy Austin yielded only three games to Australian Nerida Gregory.

No. 3 seed Chris Evert Llod, who had a first-round bye, finally played her opening match. She walloped Christine Jolissaint of Switzerland, 6-0, 6-1, and then had some interesting reflections on her nine-year Wimbledon career:

"In one sense it has been a success, because I've never done worse than getting to the semifinals," said Evert, now 25, the champion of 1974 and '76 and three times runner-up. "But in another way, Wimbledon has always been very emotional for me. Looking back, I don't think I've just played tennis here. Something else has been going on.

"Last year, it was my marriage (to British Davis Cup player John Lloyd). In years before, maybe the press has jumped on certain situations with me," she went on, alluding to her 1974 engagement and subsequent split from Jimmy Connors.

"So, I really haven't been able to play Wimbledon with a clear mind in the past. "I'm not blaming anybody. Maybe it's my fault. But other tournaments, like the U.S. Open, haven't been like that. This year, there's nothing emotional about it. I'm very relaxed, eager to play and there are no distractions at all."

Andrea Jaeger, at 15 the youngest player ever to be seeded at Wimbledon, finished up a 6-2, 6-3 victory over Californian Marita Redondo that had been suspended overnight with Jaeger ahead, 3-0, in the first set.

The gifted and engaging Jaeger, who has been looking for a park to play soccer between her matches, appeared totally unintimidated by Centre Court, the stately 14,000-seat (plus 3,000 standing-room places) Elizabethan-style arena that has turned so many player's knees to jelly on their debut there.

"Yesterday I was awed, just a little, but today I wasn't. Once you see the place, and see how many people there are, it's different," she said. Mostly, she was relieved that she didn't have to curtsy to the Royal Box, since there were no royal spectators present at noon.

Four of the lesser women's seeds were beaten today: No. 12 Virginia Ruzici, runner-up to Evert Lloyd in the French Open, by JoAnne Russell, 6-2, 3-6, 6-4; No. 13 Sue Baker by Bettyann Grubb Hanson Stuart Dent, recent bride of Australian player Phil Dent, 3-6, 7-5, 6-2; No. 15 Regina Marsikova by Australian Sue Saliba, who is more comfortable on grass courts, 6-2, 3-6, 6-1, and Hanika, also a clay court specialist who changed to an unaccustomed serve-and-volley game.

Shriver led Hanika 3-0 and 5-3 in the final set, butchered an easy backhand volley on break point when she served for the match, saved a break point on her serve at 5-5, failed to cash three match points at 6-5, saved two more break points at 6-all, then finally broke Hanika on her fifth match point. The match was an emotional roller-coaster ride.

"I was really nervous. I had visions of missing three match points and losing 8-6 in the third, like I did to Barker on Centre Court," said Shriver, recalling her introducing to Wimbledon two years ago. "I was just glad to get this one over with."

Said Don Candy, Shriver's Australian-born coach. "I was 51 years old when I started to watch that match, and 54 when it finished, going on 55. Pammy was a little frightened, a little tentative, but she came through. In the last game, even with Sylvia serving, Pam was the aggressor. She kept chipping and coming in, chipping and coming in. In was good win."

Actually Shriver, the 6-foot "Great Whomping Crane" from Lutherville, Md., played extremely well to get to the match points, but then babied them. She was volleying solidly and fearlessly, sliding nice backhand returns down-the-line and getting to net, but sailing her flat, sometimes awkward forehand and lobbing poorly.

"The thing that encouraged me was the way Pam kept fighting," Candy said.

"She didn't serve well at all, and some days like that I've seen her turn it in, figuring there's no future in it. But she hung in there and showed some courage. Sylvia can't volley any better than she did today: she's not a serve-volley player, but she was blood good at the net. Pam had to keep pressing her, and she did."

McEnroe -- who also came into Wimbledon as the second favorite to Borg last year, but was beaten by Tim Gullikson on the soft, chopped-up turf of Court 2 -- played on an even worse court today. He neither served or returned serve well, and flirted with another early exit.

The Court 3 grass was what cricketers call a "spinner's wicket" -- soft and uneven, so that it was impossible to tell whether the ball would sit up or skid through or hardly bounce at all.

Under the circumstances, McEnroe found no rhythm against Rocavert's nicely controlled game. He mis-hit many returns, and even whiffed completely on one -- "a fresh air ball," in the British idion.

He also was tossing the ball too low on his serve, missing an unconscionable number of first serves, and having trouble getting out of the hole he dug with his foot at the baselne and up to the net for good volleys. Until he moved over and served from a wider angle he lost two sets.

"It wasn't one of my best days, let's put it that way," said McEnroe, who had to hold serve to save the match at 4-5 and 5-6 in the fourth set, and double-faulted for the ninth time to go 1-2 down in the ensuing tiebreaker.

"Losing crossed my mind at that point," admitted McEnroe, but Rocavert, 25, who is ranked No. 112 in the world, was not there to answer the door when opportunity knocked.

On the next point, he netted an easy forehand from midcourt -- "I was trying to figure out whether to hit it to his forehand or backhand, and thought a little too much about that," he said.

Then he netted a low forehand volley and played three more bad points to fall irrecoverably behind in the tiebreaker, which McEnroe won, 7-3.

One service break decided the final set. Rocavert double-faulted to 0-40 in the sixth game, saved two break points, then double-faulted again, for the 19th time in all, to lose serve.