Ivan Lendl and Jimmy Connors, the two top-seeded players, each scored straight-set victories Saturday to advance to the final of the $150,000 Executone Hamlet Challenge Cup at Jericho, N.Y.
They will meet today for the $35,000 first prize in a final tuneup for the U.S. Open, which begins Tuesday.
Lendl, the defending champion who is seeded No. 1, defeated unseeded Paul Annacone of Bridgehampton, N.Y., 6-3, 7-6, fighting off three straight set points before winning the second-set tiebreaker.
Connors, seeded second, defeated fifth-seeded Miloslav Mecir of Czechoslovakia, 6-2, 7-5.
Boris Becker of West Germany came back from a two-hour rain delay and served three aces to defeat Joakim Nystrom of Sweden, 6-4, 7-5, in the semifinals of the Assn. of Tennis Professionals tournament at Mason, Ohio.
In today's final, Becker will face top-seeded Mats Wilander of Sweden, who defeated Tim Wilkison of Asheville, N.C., 6-2, 6-1.
Becker's victory was highlighted by a somersault by the 17-year-old Wimbledon champion. Trailing 4-5 in the second set and with the score 15-15 in the 10th game, Becker did the somersault as he came up to hit the ball and win the point. He ended up winning the game to tie the set, 5-5.
He performed the same kind of feat at Wimbledon this year.
"The roll was an important point, though it was harder than on grass," Becker said. Wimbledon is played on grass, the ATP on clay.
At Monticello, N.Y., Helen Kelesi, a 15-year-old Canadian, scored her third upset of the week with a 7-6, 7-6 victory over top-seeded Helena Sukova of Czechoslovakia to advance to the final of a Virginia Slims tournament.
Kelesi will meet second-seeded Barbara Potter of Woodbury, Conn., who was ahead, 7-6, 2-1, when third-seeded Sylvia Hanika of West Germany retired, complaining of a pulled thigh muscle.
Kelesi, of Victoria, British Columbia, is ranked 64th in the world. Earlier, the 5-5 teen-ager ousted Katerina Maleeva and Virginia Ruzici.
In the second round of U.S. Open qualifying at New York, Leonardo LaValle of Mexico, the Wimbledon junior boys' champion, defeated Craig Kardon of Dallas, 6-3, 6-2. A victory today over Olli Rahnasto of Finland would give LaValle a spot in the main draw of America's premier tennis event, which begins its 13-day run Tuesday at the National Tennis Center.
Sixteen of the 128 players in the men's qualifying will gain the main draw. There are eight spots in the women's main draw for the survivors among the 64 players who began qualifying Friday.