Fifth-seeded John McEnroe and sixth-seeded Henri Leconte were defeated by a pair of unseeded opponents Tuesday night in first-round play at the Assn. of Tennis Professionals Championship at Mason, Ohio.
McEnroe lost to Paul Annacone, 7-6, 6-4, and Frenchman Leconte was beaten by Jonathan Canter, 6-3, 7-5.
McEnroe hurt his back at the end of the first set but continued to play.
"It's something I think I can get over in three or four days," he said. "This is my first setback in six weeks, so I'm still optimistic."
In other night matches, second-seeded Stefan Edberg of Sweden defeated Jimmy Arias, 6-4, 6-3, and Christo Van Rensburg of South Africa beat Ronald Agenor of Haiti, 6-1, 6-4.
In Tuesday's earlier matches, Australian challenger Wally Masur upset 10th-seeded Kevin Curren, 7-6, 6-2; third-seeded Boris Becker of West Germany survived some early problems to defeat Marcel Freeman, 3-6, 6-3, 6-1, and fourth-seeded Jimmy Connors downed Jay Berger, 4-6, 6-2, 6-3.
Australian Anne Minter beat fourth-seeded Helena Sukova of Czechoslovakia, 6-3, 6-1, eliminating the defending champion from the $293,000 Player's Challenge tournament at Toronto.