WIMBLEDON, ENGLAND, JULY 2 -- The incessant bobbing of 14-year-old Jennifer Capriati's ponytail would make anyone else seem old, and how quickly Steffi Graf's youth has passed. Graf, the 21-year-old defending champion, seized Capriati by that hank of hair and flung her out of Wimbledon today, 6-2, 6-4.

Capriati is called the future, a frightening apparition of the era of force who has broken records with her youthfulness. Scant months ago it was Graf who was viewed as callow, and it seemed she wanted to push the coming generation back as she defeated Capriati with startling conviction today to reach the quarterfinals. Their long-awaited first meeting produced bashing from the Centre Court baseline, and Graf ended it after 59 minutes by burying a classic forehand winner in the opposite corner.

Everything 12th-seeded Capriati hit, top-ranked Graf hit harder, better and more often. Capriati, whose chief attribute is power, was reduced to a scrambling little girl in the face of Graf's force, never able to gain so much as a break point. Capriati emerged from the defeat cheerful to have made a respectable debut on Centre Court before the Duchess of York, whom she referred to as "Princess Fergie," and awed by Graf's winners.

"Now I know why they call it 'The Forehand,' " Capriati said. "Another ball always came back. She was just too explosive, too powerful."

There were no vestiges of childishness left in Graf, only a dignified maturity as she overcame both physical and emotional problems for a victory that should do wonders for her shaken confidence. She has had little respite from ugly tabloid stories or a painful sinus inflammation. She flew to West Germany over the weekend for medical treatment of the sinus condition she said will require surgery after the season.

"I really wanted to win this match after the way I've felt," Graf said. "I was just trying to get myself together and try as hard as I could. So I'm happy to win."

Nor is Graf apt to get any respite from the encroaching younger set represented by Capriati and 16-year-old Monica Seles, the Yugoslavian who defeated her in the French Open final last month. Graf likely will soon confront Seles, who reached the quarterfinals with a 37-minute 6-1, 6-0 dismissal of 30-year-old veteran Ann Henricksson to extend her winning streak to 36 matches, including six tournament titles. They are projected semifinal opponents.

But first Seles, playing in only her second Wimbledon, must surmount fifth-seeded Zina Garrison, a 6-3, 6-3 victor over No. 10 Helena Sukova. Garrison, a 26-year-old from Houston, has been quietly brilliant, losing just 15 games in making the 11th Grand Slam quarterfinal of her career.

The meeting between Graf and Capriati had been anticipated since the Florida eighth-grader turned pro three months ago. It was irresistible. They have the heaviest strokes on the women's circuit save for perhaps Seles, so it seemed appropriate that their first encounter should come at Wimbledon, on Centre Court. No. 2 Martina Navratilova played in a veritable vacuum next door on Court No. 1 as she brushed off her first seeded opponent of the tournament, No. 14 Judith Wiesner of Austria, 6-3, 6-3. At 33 the oldest player in the draw, Navratilova raised her Wimbledon match record to 96-9.

Also advancing in straight sets were No. 4 Gabriela Sabatini, No. 7 Katerina Maleeva, No. 11 Natasha Zvereva and No. 13 Jana Novotna.

The Graf-Capriati match was in keeping with a long Wimbledon tradition of pitting ingenues against reigning champions. It dates from 1919, when Suzanne Lenglen of France upset seven-time champion Dorothea Lambert Chambers of England. In 1962 Billie Jean King was an 18-year-old who stunned Margaret Court in the first round. In 1972 Chris Evert was a teenage phenom who extended defending champion Evonne Goolagong to three sets in a dramatic semifinal. In 1977 Evert was the chased champion, meeting a 14-year-old named Tracy Austin in the third round. Evert shook with nerves but taught Austin a 6-1, 6-1 lesson.

Graf was more than aware of the circumstances; today was an anniversary for her. She was 15 years 18 days old when she met Jo Durie of England in the round of 16 on this date in 1984. She extended Durie to three sets to let the tennis world know she would soon be coming, 3-6, 6-3, 9-7.

"I have to say it is strange," Graf said. "To be just 21 and have to play so much younger girls. It's strange, because I don't feel old. It's just weird."

Capriati routinely has been the youngest player in history to achieve whatever she set her hand to, whether it was making the final of two of her first three pro tournaments, reaching the semifinals of the French Open, or making the round of 16 in her debut at the All England Club at 14 years 95 days. The situation could have easily made Graf nervous, but she was impervious. Capriati also was unmoved by the circumstances, only "hyper," she said, over the beginning of what may be both a long rivalry and pleasant association, the two chatting amiably earlier in the tournament.

"You know she is such a favorite because she is so young and so natural, and people like her," Graf said. "She has always wanted to play me and I was looking forward to it too, and we were on Centre Court at Wimbledon. It was a great way to start."

The quality of tennis, however, did not meet the occasion. The score mounted almost as quickly as Capriati played, the teenager moving between points so breathlessly she made the efficient Graf look sluggish. But Graf commanded the match from the opening moments, as she broke Capriati's serve in the first game.

Capriati aided her with a double fault, and Graf sealed it with a sharply angled forehand winner. Capriati tried to wrest momentum away as she killed two set points, the first by reversing her steps to drive a backhand pass across the court, the second with a perfect backhand lob. But Graf took the set with an easy volley to open court and a service winner.

Capriati yielded control of the second set as she dropped her serve in the fifth game, making a mad dash to retrieve a short ball, only to flick her backhand wide and fall behind, 2-3. Unable to make inroads against Graf's serve, the outcome was by then inevitable. Capriati mustered a service winner to kill a match point and hold for 4-5, but that only delayed Graf.

"I had a lot of fun," Capriati said. "I was just happy to be out there with her. She was great."

In just three months as a pro, Capriati has soared to No. 13 in the world and already has met the top three players. While it is reasonable to expect her to make the top 10 this year, her results also indicate how much further she must go: She was beaten by Navratilova in the final of the Family Circle Cup, 6-2, 6-4, and by Seles in the French Open semifinals, 6-2, 6-2. But she may take a cue from Seles, who last year was dismissed by Graf, 6-0, 6-1, in Seles' Wimbledon debut.

"When I've played the top three I haven't done well or come close to beating them," Capriati said. "So I've done well, but I don't think I'm up there. Next year hopefully I'll improve and do better." SEEDS' FOURTH-ROUND RESULTS MEN

Boris Becker (2), West Germany, def. Pat Cash, Australia, 7-6 (7-3), 6-1, 6-4; Stefan Edberg (3), Sweden, def. Michael Chang (13), Placentia, Calif., 6-3, 6-2, 6-1; Brad Gilbert (7), Piedmont, Calif., def. David Wheaton, Lake Minnetonka, Minn., 6-7 (8-10), 3-6, 6-1, 6-4, 13-11; Christian Bergstrom, Sweden, def. Guy Forget (11), France, 6-4, 3-6, 6-3, 7-5. WOMEN

Steffi Graf (1), West Germany, def. Jennifer Capriati (12), Saddlebrook, Fla., 6-2, 6-4; Martina Navratilova (2), Aspen, Colo.., def. Judith Wiesner (14), Austria, 6-3, 6-3; Monica Seles (3), Yugoslavia, def. Ann Henricksson, Mahtomedi, Minn., 6-1, 6-0; Gabriela Sabatini (4), Argentina, def. Nathalie Tauziat, France, 6-2, 7-6 (7-1); Zina Garrison (5), Houston, def. Helena Sukova (10), Czechoslovakia, 6-3, 6-3; Katerina Maleeva (7), Bulgaria, def. Nathalie Herreman, France, 6-3, 6-0; Jana Novotna (13), Czechoslovakia, def. Patty Fendick, Sacramento, Calif., 6-2, 6-4; Natasha Zvereva (11), Soviet Union, def. Brenda Schultz, Netherlands, 6-2, 6-2.

Centre Court

Steffi Graf (1), West Germany, vs. Jana Novotna (13), Czechoslovakia; Katerina Maleeva (7), Bulgaria, vs. Martina Navratilova (2), Aspen, Colo.; Jason Stoltenberg and Todd Woodbridge, Australia, vs. Guy Forget, France, and Jakob Hlasek (7), Switzerland.

Court 1

Monica Seles (3), Yugoslavia, vs. Zina Garrison (5), Houston; Ivan Lendl (1), Czechoslovakia, vs. Alex Antonitsch, Austria; Natasha Zvereva (11), Soviet Union, vs. Gabriela Sabatini (4), Argentina.

Court 2

Mark Woodforde, Australia, vs. Brad Pearce, Provo, Utah.