It was a moment many thought Martina Navratilova would never have again, a moment of victory over Chris Evert Lloyd.

As 18,588 fans applauded both players, Navratilova leaped into the air, her face breaking into a grin, and shrieked in joy to celebrate her 7-5, 4-6, 6-4 victory.

Today, she earned that joy with a masterpiece. She survived a courageous effort by Evert, two delays in the third set because of three rowdy fans being removed from the stadium, and her own mind games, the kind that had caused her to fold consistently the last two years.

Navratilova's victory, accomplished over an enthralling span of 2 hours 12 minutes at the National Tennis Center, puts her into the U.S. Open final for the first time. Saturday, she will meet Tracy Austin, a 6-1, 6-3 winner over Barbara Potter today in a match that was a routine footnote to the dramatics that followed.

Although she is only 24, many had written off Navratilova's chances of winning another major title. After winning Wimbledon in 1978 and 1979, her game had fallen off, her concentration had wavered. With Evert still ruling and such teens as Austin, Andrea Jaeger and Hana Mandlikova growing daily, Navratilova was rarely mentioned when this tournament began.

But she came here looking like a different player than the one who lost here in the fourth round a year ago, different than the player who was beaten by Mandlikova in the Wimbledon semifinals three months ago.

"I never worked so hard in my life the last couple of months," she said today. "I worked on having the confidence to believe I could make the shots in the nitty-gritty. It was almost like meditation, seeing the shots in my head. Forcing myself to believe again I could make them."

Today, Navratilova played almost as if in a trance. She had to, because Evert never loses easily, especially when a major title is contested. And Evert was the defending champion here.

For the first seven games, Navratilova was almost perfect. She played a nervous first game, missing four shots at net to have her serve broken for the first time in the tournament. But she broke right back with a hard forehand down the line, the kind of ground stroke her game has lacked the last two years.

Serving superbly, she began to take control, especially at the net. She pushed Evert farther and farther back, overpowering her with deep probing shots from the base line and ungettable volleys coming in behind the ground strokes.

Navratilova's serve was a weapon, Evert's often a burden.

Navratilova broke Evert in the sixth game of the first set with a gorgeous lunging backhand volley and held for 5-2. Then it was Evert's turn.

Back she came, breaking Navratilova with three straight winners, the last a forehand that Navratilova barely touched as she came to the net. When Evert survived two set points in the next game and held for 5-all, the crowd seemed to sense that Evert was back.

But Navratilova held easily, her first serve pulling her through. Evert then played a poor game, making two surprising errors to go down triple set point. She saved one with a forehand but then pushed a forehand deep and Navratilova had the first set.

"That was my problem: I only played well in patches," Evert said. "It came and went all day for me, actually for both of us."

In the second set, they played some of the most remarkable tennis ever played in this stadium. In the fourth game of the set, with Evert serving and up a break, they played 16 points. Thirteen of them were decided by outright winners. Two were classics.

The first came at break point. Twice, Navratilova hit perfect placements that Evert somehow got to. Twice Evert hit ungettable overheads that Navratilova ran down. Then a drop shot, then a perfect lob, then another drop that Navratilova again got to but, lunging almost into the audience, she caught the net tape.

The match was stopped briefly as both players received a standing ovation. Three points later, again at break point, they repeated the act. This time Navratilova punched a winner off her shoetops for the break and again the crowd was in hysterics.

They took turns breaking until, with Navratilova serving at 3-3, Evert hit another forehand down the line to get up 4-3. By now, Evert was hitting her ground strokes harder and harder, her pace picking up with each game.

But Navratilova was not folding. The unforced errors were still rare, Evert was winning points and Navratilova was not losing them. Evert served out the set after the break, even though Navratilova saved a set point with a luckout let cord volley. The second set point she wasn't as lucky, her backhand slapping the net.

Now, Evert was clenching her fist after good shots, jumping up and down to keep loose. When she broke Navratilova for 3-1 by whistling a first serve back so hard that Navratilova punched it long, she seemed in complete control.

Then came the disturbance. First at 3-2, the Garrison security men tried unsuccessfully to remove a screamer in the stands. After the delay, Evert held. So did Navratilova. During the next change, there was another delay as the security guards bodily removed Philip Greenwood, 27, of London, charging him later with disturbing the peace.

"Four years ago, I might have lost it there," Navratilova said. "But I was able to at least not let it disturb my game. After the second delay I just started coming in on everything. It wasn't anything conscious. I don't remember thinking about it. I just did it."

Navratilova broke Evert at love with three clean winners to reach 4-4. The next game decided the match.

"I should have won the set," Evert lamented. "I had so many chances. I was up a break. I had so many chances. That last game she served it was 15-40 and I couldn't finish it."

Navratilova wouldn't let her. She served an ace to get to 30-40, then came in and watched as Evert hit a backhand too deep. At deuce, Evert hit a backhand winner crosscourt but Navratilova came right back with a service winner. Evert hit a backhand wide and Navratilova had one more first serve in her to lead 5-4.

With the cool of evening closing in, the two women reached deuce, Evert saving a match point with a wonderful forehand winner. It was her last hurrah. Shockingly, she double-faulted to match point again.

Navratilova wasn't going to back off now. She followed Evert's first serve and punched a volley. Evert got to it but her backhand lob sailed long and Navratilova sailed five feet into the air in exultation.

"This means as much as anything to me," Navratilova said. "Nobody expected me to do much. Down 4-2, I thought I was going to lose. I'm proud of myself for coming back. I didn't quit."

"Maybe this is Martina's time," Evert said.

Certainly, today was her day.