Using exaggerated topspin on the clay courts at Aspen Hill Racquet Club, Mark Buckley reached the singles final of the Mid-Atlantic Tennis Association Tournament yesterday by defeating Hank Harris, 6-0, 6-4.

Buckley's opponent in today's 11 a.m. final could be his doubles partner, Scott Kidd, whose semifinal match against No. 3 seed Claude England was suspended by rain in the third set. Kidd won the first set, 7-6, then faltered, 2-6, and was serving at 4-4, England, when the rains came. The decisive set will be resumed today at 10 a.m.

Tony Velo, last year's AMTA singles champion, and Harris kept Kidd and Buckley from monopolizing tournament finals with a 6-3, 7-6 semifinal doubles victory indoors. England and Tony James reached the final by defeating Skip Bishop and Roberto Patarrieu, 7-6, 3-6, 6-4.

The 19-year-old Buckley, seeded 14th, reached the singles final by keeping Harris handcuffed and pinned deep.

"I've always played a topspin game. It comes to me naturally," said Buckley, whose shoulder and arm appear headed in opposite directions during his exaggerated forehand. "I stuck with my game, keeping it deep and coming to the net only on short shots."

The unseeded Harris lost a 3-1 lead in the second set as the court and Buckley seemed conspired to keep the bouncing ball away from him during a four-game Buckley binge. Buckley led 5-3 before both players held service to end the match.

"He's a very good clay-court player," said Harris, dizzied by trying to read all the spin thrown at him. "He used the court well and I guess I started pressing when I found myself down all those games in the first set."

Harris' inability to get his first serve in court also worked to Buckley's advantage. "If I had been able to get my first serve in," Harris said, "it would have enabled me to get on the offensivie.As it was I was the defensive all afternoon."