TENNIS ROUNDUP : Unseeded Larsson Upsets Third-Seeded Wheaton

Magnus Larsson, a 21-year-old Swede who ranks 56th in the world, upset third-seeded David Wheaton, 6-1, 6-7 (7-2), 7-6 (7-5), in the rain-interrupted first round of the Norstar Bank Hamlet Challenge Cup Tuesday at Commack, N.Y.

“It was slow and gritty on the court,” Wheaton said. “They say it’s supposed to be like the courts at the U.S. Open next week, but it’s much slower. If I knew the court was that slow I’d never have played here.”

Top-seeded Stefan Edberg defeated Chris Garner, 6-1, 6-1; and No. 4 John McEnroe beat Gilad Bloom, 6-4, 4-6, 6-1.

Radka Zrubakova of Czechoslovakia defeated Natalia Zvereva of the Soviet Union, 6-4, 7-5, in the Virginia Slims of Washington.

Zvereva said she had other things on her mind that made it “tough to concentrate.” And the Soviet is unsure about returning to her country: “I don’t think so. It won’t be safe enough for me.”

In other matches, second-seeded Aranxta Sanchez-Vicario downed Regina Rajchrtova of Czechoslovakia, 6-4, 6-4; and No. 4 Mary Joe Fernandez beat Mariaan De Swaart of South Africa, 6-4, 6-1.

Second-seeded Sergi Bruguera of Spain defeated Jason Stoltenberg of Australia, 4-6, 6-2, 6-3, in the first round of the OTB International Open at Schenectady, N.Y.