Third-seeded Art Diemar of the Bronx, N.Y., used a powerful forehand and superior quickness to defeat second-seeded Tom Ranker of York, Pa., 21-7, 21-11, for the men's open title of the first AMF Volt-Perrier Racquetball Classic at Courts Royal North in Rockville Yesterday.

Jan Campbell Matthews of La Costa, Calif., disposed of Sue Carow of Chicago, 21-17, 21-15, for the women's open crown in a match of the only two professionals in the pro-am tournament.

Ranker appeared sluggish after requiring a come-from-behind effort to eliminate fourth-seeded Ed Remen of Stering, Va., 10-21, 21-16, 11-5, in yesterday's semifinals.

Diemar, who beat Tom Whipple of Timonium, Md., 21-12, 21-19, in the semis, jumped to an 8-1 advantage over Ranker in the first game and was never challenged. In the second game, Diemar spotted Ranker a 5-3 lead before scoring nine of the next 10 points to go ahead, 12-6.

"He (Ranker) can play 10 times better than he did today. He beat me once so I know," said Diemar, who lost his only previous encounter with Ranker. "There was one stategy - not to make errors - because he makes less errors than anybody on the East Coast."

Matthews, on the comeback trail on the Leach-Seanco Pro-Am Tour after knee surgery, won her first tournament in two years by mastering an opponent who has never beaten her in four tries. She trailed in both games before prevailing.

Down 14-12 and 15-14 in the first game, Matthews notched seven of the final nine points, including the last four. In the second game, 41-year-old Carow led, 14-11 before Matthews, 15 years her junior, ran off six straight points and 10 of the last 11.

"It never occurred to me that I could lose. The only thing that occurred to me is that it could go three games and I didn't want that," Matthews said.

"The thing that bothered me was I was playing lousy.She forces people not to play their own game."

The match was marked by numberous complaints by Carow about the officiating. After the first game, she exercised her prerogative and had the referee and two linesmen replaced.

Top-seeded Bill King of Radford, Va., advanced to the men's senior (over 35) finals when fourth-seeded Jay Krevsky of Harrisburg, Pa. arrived too late for their semifinal match then had little trouble defeating peter Kortman of Gaithersburg, 21-3, 21-4, for the title.