The stately green stage is set, immaculate as always. All the principal players, under-studies and aspiring stars of tennis are ready, or hope they are, for the curtain to go up on their sport's grandest and longest-running show.

Monday afternoon, "at 2 p.m., precisely," defending men's singles champion Bjorn Borg and journeyman Tom Gorman - a semifinalist in 1971, but past his prime at 33 - will stride into the Elizabeth-style Centre Court arena of the All England Lawn Tennis and Croquet Club, onto the most celebrated lawn in the tennis world, pausing only to bow to the occupants of the Royal Box.

After a four-minute warmup, they will begin the first match of this year's Wimbledon, renewing traditions that date back to 1877.

Over the next fortnight, more than 300,000 spectators will pass through the wrought-iron gates of the picturesque All England Club. They will consume a million strawberries in cream and devour 395 matches in the official championship events: men's and women's singles and doubles, and mixed doubles.

Prize money has been increased to more than $550,000, including $40,000 for the winner of the "gentlemen's singles" and $36,000 for the winner of the "ladies' singles."

But prize money seems curiously unimportant at Wimbledon, as does commercial sponsorship, which is kept to an understated, tasteful minimum: a small Coca-Cola logo on a cooler here, a bottle of Robinson's Barley Water there, an encampment of marquees for corporate entertainment set up out back on the clay courts at the far end of the club, beyond the 15 grass courts and familiar vine-covered water tower.

"The title is the most important thing. This is the tournament every player dreams of winning. For sure, I would play here for nothing," said Borg, a $2 million a year earner who is striving to become the first man to win four consecutive Wimbledon singles titles since New Zealander Tony Wilding in 1910-13.

This year, there are a number of fascinating subplots to be savored.

Borg, just turned 23 and already established as the dominant player of the decade, is trying to extend his 28-match winning streak at Wimbledon, on a fast, skiddy surface to which he once thought he would never adapt.

Here he changes his usual back-court game, founded on incomparable top-spin ground strokes to the serve-and-volley attack virtually required by grass. But this year he faces his toughest draw, including possible early round meetings with Vijay Amritraj of India, Australians, Mark Edmondson or Colin Dibley, and Americans Peter Fleming or Jeff Borowiak - all big servers who can be dangerous on grass.

If he gets through to the semifinals, Borg likely will meet arch rival Jimmy Connors, the champion of 1974 and runner-up the past two years. And if the seedings hold true, the men's final on Saturday, July 7, will pair Borg (No. 1) against 20-year-old left-hander John McEnroe (No. 2), who has beaten him in three of five career meetings, most recently in the World Championship Tennis Finals at Dallas last month.

Connors, who expected to be seeded No. 2, was placed third instead because it was not certain until last week whether he would play Wimbledon or stay with his wife Patti, who is expecting their first child any day in Los Angeles.

"The only thing I need now is a Concorde standing by to get me to L.A. If I hear the baby is on the way while I'm still playing at Wimbledon, I don't know what I'll do," Connors said on his arrival in London. "I hope I don't have to make that decision."

But as long as he is in the tournament, Connors can be expected to give his all, for that is the only way he knows how to play tennis: ferociously.

Connors also has a tough draw. His quarterfinal opponent likely will be Victor Pecci of Paraguay, who upset him in the semifinals of the French Open 2 1/2 weeks ago. Then Borg - who has lost only 10 games in two matches against Connors this year - and probably McEnroe, who beat him in the WCT semifinals.

McEnroe, the most talked-about player in massive pretournament publicity, has become the British press' favorite whipping boy because of his often petulant behavior and surly on-court demeanor. But he is also hailed as a can't-miss future champion, perhaps the most talented, versatile and athletic man playing the game today.

In 1977, Wimbledon's centennial year, McEnroe came through the qualifying rounds and reached the semifinals at age 18, the youngest player and only qualifier ever to get that far. Last year he was upset in the first round by Erik van Dillen.

Can he win this year and become the fourth youngest champion in history?

"No one knows. A certain amount of luck is involved, but he's certainly capable of it," said 1975 champion Arthur Ashe, who harbors hopes of becoming one of the oldest champions at 36.

"But there's no doubt in my mind that McEnroe will surpass Borg and Connors and be the No. 1 player in the world within two years. He is a genius with a racket."

In the women's singles, 1974-76 champion Chris Evert, newly wed and perhaps approaching the end of her career at 24, and defending champion Martinia Navratilova, 22, are seeded to meet in a rematch of last year's absorbing final, which the expatriate Czech left-hander won, 2-6, 6-4, 7-6.

That victory established the volatile Navratilova as a bona fide champion, but Evert did not lose another match the rest of 1978, won her fourth straight U.S. Open title, and snatched the International Tennis Federation's designation as world champion from Navratilova.

Navratilova dominated the first part of 1979 as she did the first six months of 1978, winning the Avon Championship at Madison Square Garden in March, and then took most of the spring off as Evert lost her six-year, 125-match clay court winning streak but regained the French Open title.

Evert versus Navratilova has developed into a splendid rivalry. Their equality was never more vividly demonstrated than on Saturday afternoon when Evert survived three match points and beat Navratilova, 7-5, 5-7, 13-11, in a marvelous three-hour final to the Colgate Championship at Eastbourne, England.

Teen-agers Tracy Austin, 16, and Pam Shriver, who will turn 17 on July 4, have helped give the women's draw more depth than it has had in a decade, but both are nursing troublesome injuries.

Austin was runner-up to Navratilova in the Avon Championship and ended Evert's clay court streak in the Italian Open, but she pulled a groin muscle at Eastbourne last week and defaulted her semifinal.

Shriver, last year's U.S. Open runner-up, is seeded only No. 16 because she has played little since last September, concentrating instead on completing her combined junior and senior years at McDonogh School in Baltimore.

But her attacking serve-and-volley game and superb sliced approach shots are ideally suited to grass, and she could give Evert a battle in the fourth round if she isn't too bothered by strained shoulder muscles that have affected her serve.

Billie Jean King, 35, still is seeking a record 20th career Wimbledon title. She has won the singles six times, the women's doubles nine times and the mixed four times, tying her with Elizabeth Ryan, who won 11 women's doubles and eight mixed titles between 1914 and 1934.

King originally did not plan to enter the singles this year, because she has had little competition since surgery on her foot last December, but she was granted late entry after crushing Navratilova in a tune-up tournament at Chichester two weeks ago.

She and Navratilova also are top-seeded in doubles and King, though bothered by a pulled groin muscle, feels this may be her year to finally achieve a record she dearly wants.

Evonne Goolagong Cawley, the lithe and incomparably graceful Australian who won the title in 1971, is fit and in form again, seeded No. 3 and likely to meet 1977 champion Virginia Wade in the quarterfinals, then Evert in the semis.