The timekeeper at the National Tennis Center is justifiably confused. Some players in this year's United States Open championships want to turn back the clock; others want to twist it ahead.
The men's draw has seen such ''oldtimers'' as Ilie Nastase, Bob Lutz, and Jaime Fillol play as they did a decade ago. Among the women, meanwhile, a host of teen-agers have behaved as if this were 1992 and they were in the prime of long careers.
These girls, of course, are probably too young to remember how Nastase won this same tournament on the grass rectangles of Forest Hills in 1972. He beat Arthur Ashe that year in the final, and now has recalled some of his former brilliance to beat his first three opponents here.
His latest victory came at center court Sunday, where he toppled 10th-seeded Johan Kriek in five sets and set up a match with Jimmy Connors. They once were the bad boys of tennis, a couple of tennis mavericks who enjoyed clowning around in doubles.
Lutz and Fillol join Nastase in the elder statesmen category. Ilie, however, actually will never be known as a statesman, and was fined $1,000 for verbally abusing a linesman in Sunday's match. Lutz, 35, has won the Open doubles title on three occasions (1968, '74, and '80) with Stan Smith, while Fillol, 37, has no major titles but has been a steady laborer and labor leader in the tennis vineyard for years.
The three players are generally thought to be in the twilight of their careers, and certainly near the end of their ropes in the current competition.
At the opposite end of the sprectrum are the teen-agers making waves in the women's draw. Eight Americans, ranging from 15 to 19, are among the ''sweet sixteen'' survivors, including defending champion Tracy Austin and fourth-seeded Andrea Jaeger.
Other members of this star-spangled kiddie corps are Zina Garrison, Bonnie Gadusek, Kathy Rinaldi, Gretchen Rush, Vicki Nelson, and Andrea Leand.
More than 200 competitors have been jettisoned from the Open thus far, including such seeded players as Vitas Gerulaitis, Billie Jean King, Barbara Potter, and Jose-Luis Clerc. The big four, however, remain intact in both the men's and women's singles as the tournament enters its concluding week.
If the established cream continues to rise, defending champion John McEnroe would meet Ivan Lendl in one men's semifinal, and Connors face Guillermo Vilas in the other. Among the women, it would be Chris Evert Lloyd versus Jaeger, and Austin going against Martina Navratilova.
But of course no one counts his chickens before they hatch here at Flushing Meadow in Queens. A surprise or two may still be incubating.
Lendl perhaps feels most threatened, since his path to the semifinals looks especially treacherous. If he should get by Mats Wilander, who beat him in the French Open, his next hurdle would probably be France's Yannick Noah, who defeated Lendl in Davis Cup play earlier this summer.
This looks like a bed of hot coals considering the way Wilander and Noah have been playing. In making his Open debut, Wilander has adjusted quickly to the swirling winds, restless crowds, and roaring jets that make this Grand Slam event uniquely challenging. In three matches, he has yet to lose a set. Noah has never gotten by the fourth round here, but has seems to be taking his newly won status as a Top 10 player to heart. Exhibiting amazing quickness for a man of his size, the 6 ft. 4 in. protege of Arthur Ashe has produced some of the tournament's most spectacular shotmaking.
Some early matches were disrupted by rain, but a real thunderstorm ensued when perennial big server Roscoe Tanner met up with 6-6 Chip Hooper, who joins Zina Garrison at the leading edge of the black tennis movement in this country. In perhaps the most scintillating match to date, Hooper gunned down Tanner 6-7, 7-6, 4-6, 7-5, 7-6, then spiked his racket to the court. The next time out, however, he lost Tom Gullikson.
While never achieving Hooper's velocity, McEnroe began to serve with his old authority in breezing past Vince Van Patten in the third round. The performance restored some of the confidence and fire that seemed to be lacking in earlier matches. Riddled by injuries for much of the year, McEnroe still has yet to relinquish a set and may be gathering momentum.
Among the leading women, it is a slim Evert Lloyd who has been most dominating, having lost just six games in three matches. She is particularly keen to end Navratilova's Grand Slam bid if they should meet in the finals. Navratilova, though, is rolling merrily along right now, as are Austin and Jaeger.
If any of them should become overconfident, real trouble could lie ahead. Pam Shriver, Hana Mandlikova, and Wendy Turnbull are former Open finalists still in the running, and let's not forget about all those fresh, young faces waiting in the wings.