For John McEnroe, there is only one "he" in the world. The whole masculine gender is, for him, epitomized by the name Bjorn Borg.

For Chris Evert Lloyd, there is only one "it" in the tennis universe. The pronoun is reserved for Wimbledon.

When McEnroe says, as he often does, "I know I can beat him," he always means Borg. When Evert says, "I'm sure I can win it," she mean Wimbledon.

Much of the core of the championships that will begin for the 104th year upon the lawns of the All England cup Monday will center on how America's best "gentleman" and "lady" player cope with their personal tennis obsessions. Can McEnroe do what no man has done in five years: beat Borg on the Centre Court grass that has become the 25-year-old Swede's personal celebratory kneeling ground? Can Evert, the ruler of all surfaces except the fast, erratic grass of Wimbledon, overcome what has been (by her standards) a bad record here: two titles in nine years, including three consecutive defeats in the final?

Aside from the royal wedding next month, those are the two most prevalent topics of London conversation. Can McEnroe, the brash, unpopular No. 2 seed, beat Borg, whose pluck, gallantry and reserve have almost made him an honorary Briton? And can top-seeded Evert, embraced here since showing the good taste to marry an Englishman, win the one event that is her nemesis?

Entire conversations with McEnroe concerning Borg -- the state of Borg's rusty game, his mysterious injuries, his unshakable tenacity of mind, the recent changes in his superstitious practice habits -- can begin and end without Borg's name ever being mentioned. "He" is Borg.

For McEnroe, unchallenged as the world's second-best player, no other opponent is worthy of discussion. This afternoon, McEnroe took a glimpse of Centre Court (silent and deserted under tarpaulin), then walked away. Whatever he felt, he hid. When you are the wrong half of perhaps the greatest Wimbledon final ever, you wait your chance for revenge.

"I've digested it; it's gone," said McEnroe of the match 50 weeks ago when he fought off seven match points to win the fourth set, then took Borg to the extremity of 8-6 in the fifth.

"Because it's early in my career, hopefully, I can learn from that, instead of being held back by it," said the 22-year-old, whose tactical remedy for fading in that last set was to cut out "junk food" this year and slowly lose about 20 pounds.

Last year, McEnroe was on his best Centre Court behavior, trying to convince the English that he was not "Superbrat," as they dubbed him. And he lost. To cheers. "Yeah," concluded McEnroe cryptically, "the English love losers." This year, McEnroe's offcourt campaign continues to convince press and fans that he's no bad fellow, just a competitor so highly strung that his edge will vanish if he must act civilized and creative at the same time.

McEnroe may no longer care about British sensibilities. Last weekend at the Queen's Club he berated a woman umpire, then even swatted a ball at her. So much for resolutions. If it takes bad manners to win, then against Borg, bad manners it may prove to be.

McEnroe knows, as all England knows, that this may be the hour to unseat Borg and claim the worldwide tennis glory that will go to the man who ends a winning streak -- 35 straight matches at Wimbledon -- that may be comparable in difficulty to, say, Joe DiMaggio's 56-game hitting streak in baseball.

Borg, who will begin this year's play at "precisely 2 p.m." on Centre Court against Peter Rennert, has played only four tournaments this year because of shoulder tenderness. His victory in the French Open does not completely erase the memory of his March-April loses to McEnroe, Rolf Gehring and Victor Pecci.

"Some think that Borg is not yet hitting the ball as consistently deep as he would like," offered three-time champion John Newcombe.

"Let's hope so," grinned McEnroe, "but you never know about Borg's injuries -- if he's hurt, or how much. There's lots of talk, but then he just plays the same as ever -- great."

Has Borg, since settling down with wife Mariana Simionescu, become a less-than-hungry homebody? Also, how dare the Swede change his religiously strict pre-Wimbledon ritual? This month, most of Borg's sessions have been at Lensbury rather than his old, less-ritzy haunt, the Cumberland Club. Borg has even had a tiny flap with Wimbledon officials, getting his dander up about the rule restricting players to just one hour of pretournament practice on the sacred courts.

"The most incredible thing about Borg's streak," says McEnroe, "is that I don't even look at him as a grasscourt player."

McEnroe, with his fierce serve-and-volley game, has spendid lobs and overheads, thinks that he is the perfect versatile grass-court player, while Borg is still primarily the beast of the back court with unequaled passing shots on the run.

Both Borg and McEnroe have draws that they like. Borg, for instance, faces few threats in his half of the draw -- possibly Victor Amaya, Brian Teacher, Kevin Curren or Johan Kriek -- before a probable semifinal meeting with Jimmy Connors, whom Borg has owned for years.

McEnroe will not have to face Gene Mayer, the No. 5 seed who withdrew with a wrist injury, nor will he see Connors, who gives him a tough match. Yannick Noah and either Roscoe Tanner of Ivan Lendl in the semis may be McEnroe's toughest early tests.

Ask Borg and McEnroe whom they would like most to duck and Borg might say Tanner while McEnroe might point at Connors; both have their wish.

If the men's final has a fair chance of holding form, the women's singles is wide open, with all the top five seeds having plausible reasons for victory on their side.

The top two seeds have nagging injuries: Evert (right knee) and Hana Mandlikova (sore lower back, hasn't practiced this week). No. 3 Tracy Austin won crisply over No. 5 Andrea Jaeger in the Eastbourne final Saturday, but she remains under the shadow of a sciatic nerve problem that sidelined her five months.

The angriest woman has been Martina Navratilova, insulted at being seeded fourth rather than third. Her rage has quieted slightly since she analyzed the draw: her three most aggravating back-court rivals -- Evert, Austin and Jaeger are all in the other half, while Mandlikova, the French Open champion, seems less imposing.

In this sport of children, Austin, who just graduated from high school, and Jaeger, 16, are practically dowagers. This year, 14-year-old Kathy Rinaldi of Florida will become Wimbledon's youngest competitor since 1907.

Should Mandlikova prosper here, a nice tiff is brewing. Since the 19-year-old Czech won the Australian Open last November, as well as the French in May, does that mean she has won two legs of a grand slam already? Or is the Australian Open clearly part of '80?

The British press has taken up the chorus that Mandlikova is halfway home. Evert gave her opinion in one word: nonsense, or something like that. That's an opinion shared by McEnroe. It's time to cut out the foolishness here, they think.

They are an odd pair, America's best two players. Evert is supposed to be an ice maiden when, in fact, she is saucy and sassy. McEnroe, outwardly truculent and sour, may, in fact, be a young artist who is simply too spontaneous for his own good.

At any rate, tennis' greatest stage is about to open the curtain on its first act. Before the overture, only one wish is held in common by all 128 men and 96 women. It is written out on the No. 1 Court's new electronic scoreboard: "No rain this year, please," begged the computer.