NEW YORK, SEPT. 11 -- David Wheaton, the 17-year-old junior who took Ivan Lendl to three sets in the Sovran Bank/D.C. National Tennis Classic in Washington in July, advanced to the final of the junior boys singles here with a 6-4, 7-6 (7-3) victory over David DiLucia.

Wheaton, seeded sixth in boys division, will face the Soviet Union's unseeded Andrey Cherkasov, a 6-4, 6-3 upset winner over top-seeded Jason Stoltenberg of Australia, in the final.

Wheaton, who is from Excelsior, Minn., was a wild-card entry in the Washington tournament. Here, he has won five straight matches without dropping a set, including a 6-0, 6-3 win over third seed Diego Nargiso.

Saturday's schedule for the men's singles semifinals and the women's final will be Mats Wilander-Stefan Edberg at 10 a.m., followed by Jimmy Connors-Ivan Lendl. The women's final will follow. The early start may be because of the threat of inclement weather in the New York area and because the Mets are engaged in a critical three-game series against the St. Louis Cardinals across the street.

Officials have begged fans to take public transportation to the final this weekend, fearing a crush of traffic similar to the two-hour traffic jams in Queens last year when the Mets' schedule conflicted with the Open.

Lendl is within striking distance of one of the longer men's records in Open history -- winning the Open without losing a set.

Neale Fraser was the last man to win the Open championship without dropping a set, winning 21 consecutive sets to win the 1960 championship.

So far, Lendl has won 15 straight sets without a loss, his closest shave being a tie breaker in the third round against Anders Jarryd. Wilander had won 13 straight sets before losing the second set Thursday in his 6-3, 6-7 (7-5), 6-4, 7-6 (7-0) semifinal victory over Miloslav Mecir.

Martina Navratilova last pulled off the feat on the women's side in 1983, winning 14 consecutive sets. So far this year, including yesterday's romp over Helena Sukova, she has won 12 consecutive sets. Top-seeded Steffi Graf also had not lost a set before dropping the first in today's match with Lori McNeil . . .

In his quarterfinal victory over Ramesh Krishnan Thursday, Edberg found himself locked in a 38-point, 16-deuce game that lasted 24 minutes.

Edberg had 10 break points and Krishnan seven game points before Edberg finally won the game to take a 3-0 second-set lead. He won the match in straight sets.