The question was not meant to be funny but Jimmy Connors laughed, anyway: "Why," someone wanted to know, "is the crowd always behind you when you play here?"

Clearly, Connors savored the fact that such a question was asked. He had just finished beating Eliot Telscher, 6-1, 3-6, 6-3, 6-0, in an occasionally spotty, occasionally wonderful U.S. Open Tennis quarterfinal. Throughout the match, the crowd cheered Connors, not out of disrespect for the gutty Teltscher but because they wanted to see Connors in the semifinals.

It has not always been that way, however. In 1977, the last time this tournament was played at Forest Hills, Connors was booed during his loss in the final to Guillermo Vilas and stormed out of the stadium without waiting around for the trophy presentations.

But that was three years ago, when Connors was 25 and still fighting Bjorn Borg for supremacy in tennis. Tuesday, Connors turned 28. He is married and a father. That has changed his image. His behavior on the court still offers plenty of bravado and flair but shouting matches with umpires and spectators are aberrations now, not the norm.

But perhaps the biggest factor in Connors' emerging popularity is the one Connors would like to forget: he doesn't win as much anymore. Connors' win today put him into a major-tournament semifinal for the sixth consecutive time in the last two years. But in none of the previous five majors has he gone any further. He has not been in a major final since he won here in 1978.

Suddenly Jimmy Connors is the underdog. In a tennis world where Bjorn Borg, 24, and John McEnroe, 21, are the dominant figures, Connors is the elder stateman, trying to get his game together long enough to win one more major before it's too late.

"I think a lot of the fans are aware of the fact that Jimmy's 28 now," said Doug Henderson, a close friend the last six years who acts unofficially as Connors' bodyguard during the tournament. "They know a guy can only play the game for so long. When they come out, they want to see him do well because a lot of them don't know how many more years he's going to be around."

Henderson first met Connors in 1974 at Forest Hills. He was in the locker room -- thanks to a friend who was a member of the West Side Tennis Club -- and he found himself sitting with Connors watching Chris Evert, then Connors' girlfriend, play a match. The two started talking and quickly became friends. They have remained close since.

Now, whenever Henderson has time off from Lehman College, where he is a senior, he tries to see Connors play.

"Jimmy's changed the last couple of years, no doubt about it," Henderson said. "He's much more mellow. Things don't make him uptight like they used to.

"Part of it is being married and being a father. Part of it is just growing up. He has a better rapport with people now; with the press for example. Jimmy's like a lot of other people: people just like being liked more than they like being hated."

The Connors who refused to talk to reporters here two years ago; the Connors who stormed out of Wimbledon after losing to Borg in 1979, is gone.

Now, Connors sits, sips a soda and will talk all day if need be. He almost appears to enjoy it.

When a female reporter asked today if Connors intended to keep the beard he initially grew to hide an infection, Connors said, "Well, do you like it?" h

"No," answered the reporter.

"Then I'm going to keep it," Connors said, "just to make you mad."

Earlier, he had been asked if he would talk about the tactics he might use when he plays McEnroe in the semifinals.

"No, I don't want to talk about it," he said. Then quickly: "I'm not trying to be bad, really. It's just that he has to play tonight (against Ivan Lendl) and I don't want to talk about it. I'm not going to press or anything just because it's the semifinals. I'm just going to try and hit the ball like I did today. If I do that, I'll be happy."

The last time Connors and McEnroe met was at Wimbledon in the semifinals. During McEnroe's four-set win, the two exchanged harsh words on several occasions. Once, Connors told McEnroe to be quiet and later told him that his son, Brett, less than a year old, behaved better than he did. The two haven't spoken since.

But Connors doesn't want to create controversy anymore. He ducked questions about the incident today. "Did I say that?" he asked when someone brought up the Windledon exchange. "That's over; it's in the past. I'm not worrying about it."