Her car caught on fire, and JoAnne Russell had a wonderful time this week at Wimbledon, where she won twice after being a point from defeat to reach today's quarterfinals against Martina Navratilova, who showed her how the superstars get super.

(Did he say her car caught on fire?)

In her tennis sweats, she lay down in the middle of the street to flag down a ride to Wimbledon, where she earned the biggest paycheck of her career, almost $12,000, and discovered that at 27 she can be a winner on the women's tour.

(Did he say she lay down in a London street?)

All this after a career so obscure the New York police only wrote a note to a weirdo asking him to stop harassing her, an obscurity so profound that the U.S. and British chapters of the JoAnne Russell fan club have four members, all here to applaud their heroine.

(Did he say the cops wrote the weirdo a pretty-please note? Her fan clubs have four members? Has this guy been at too many pubs too many nights?)

On any scale of delight, JoAnne Russell weighs heavily. Everybody knows Martina and Billie Jean, Tracy Austin and Chris Evert Lloyd (the FBI once sent armed agents, not a note, to protect Chrissie on a plane). But the 20th-best player, we don't know. Her name is JoAnne Russell, and you'd love her.

"The touring pro from Runyon's," she calls herself, Runyon's being a chatty saloon on New York's 51st Street. While her smile happens so quickly and with such conviction as to mesmerize, you're her prisoner for sure once you've heard the stories. She is Joan Rivers in a tennis skirt.

"I always have a lot of strange people at my matches. For a year, this one weirdo was sending me letters," she said. "A real wimp. Somebody told me I could outrun him if he ever bothered me, and I said, 'Did you ever see the Son of Sam? Not one of those people ran away from that guy.'

"The weirdo kept sending me letters with a self-addressed, stamped envelope for me to answer. I asked the police to call this man and tell him to stop writing to me. Scare him or something. Sgt. Walsh said, 'I'll give him a little ring.'

"They came to me and said, 'Sorry, his phone is unlisted.' " Russell threw up her hands. "And he's the police, New York's finest."

So New York's finest asked the pro from Runyon's what to do. "Write him a note," she said, kidding. They did.

As adventures go, the wimp/correspondent is small potatoes next to Russell's car ride to Wimbledon last week.

She ordered a courtesy car for 8 a.m. For her noon match. The car arrived at 1:40 p.m., by which time Russell had explained to tournament brass she would be late.

"So this girl arrives with the car and says we'll be at Wimbledon in 15 minutes. Hey, I thought she was A.J. Foyt. She like revved this car and we're going her 'own way' to the club. We get into the seamiest neighborhood, and I notice like what? Steam coming up out of the dashboard.

"The driver says, 'My, I think we're on fire.'

"The car was catching on fire. The electrical system. It rolled to a dead stop. This is two hours after I'm supposed to be on the court at Wimbledon. I'm laughing hysterically."

In this case, there's only one sensible thing to do.

"I lay down in the middle of the road," Russell said, "figuring that somebody would have to stop. I got up when this one car wasn't going to stop. Finally, another Wimbledon car came along and we flagged it down.

"I got to the club and they said, 'You go on in 10 minutes.' I'd been ready for the car at 8 a.m. And we ended our match (because of a rain delay) at 8:45 p.m."

In nine years on tour, Russell has won two minor-league tournaments and reached the semifinals of six more. Her advance to the quarterfinals here--although unseeded, she beat No. 8 Mima Jausovec and No. 9 Sylvia Hanika--is her finest work at Wimbledon. In two of four victories, all accomplished in life-or-death third sets, Russell came back from match point down.

"Beating Mima was a great win for me," said Russell, who counts Jausovec equal to any woman outside the Navratilova-Lloyd-Austin troika. "I was down 15-40, double match point, and came back. I came back from some unbelievably tight situations. I made the necessary shots to tie and to win. That's an added dimension to my game."

A solid serve-and-volley player who should do well on grass, Russell figures she yet was unseeded here for good reason. "The difference between being No. 1 and unseeded . . .is that on the big points, Martina comes up with a huge serve." In Navratilova's 6-3, 6-4 victory over Russell today, she made every point that seemed important.

And what now for Russell, who at her own level this week proved she can win the killing points?

"Hey, I'm gonna win some tournaments. I said in the locker room today that I was going to a $10,000 tournament in Erie, Pa. Those girls are laughing at me. They said, 'After Wimbledon, your ranking will go up for the U.S. Open. All you can do by playing out there is make it drop.'

"And I said, 'Yeah, and what kind of player will I be if I don't play?' You gotta win someplace. Martina didn't start out winning Wimbledon."

Runyon's should set 'em up tonight.