Two expert chess players beat the computer and a third match ended in a probable draw in a $2,600 tournament designed to see how far machines have advanced against men.

None of the players said they were nervous about sitting across a chessboard from a computer terminal, but Ron Zaffuto wore his lucky baseball cap. "It gives me confidence," he confided shortly before the beginning of the three-day, round-robin tourney at Carnegie-Mellon University.

Zaffuto, 30, who answers customer complaints for United Parcel Service, beat Nuchess, a computer at Northwestern University.

Computers consider 130,000 chess moves a second, compared with one a second by man. But that does not mean the machines have the advantage.

"The human is a lot smarter at what he'll look at," said Hans Berliner, a senior computer research scientist at Carnegie-Mellon.

Because of their understanding of the game, humans can eliminate moves while computers search all possibilities, he said.

The Fredkin Prize Committee has a standing offer of $100,000 for anyone who can design a computer program that checkmates the world chess champion.

The Pittsburgh players, all rated experts by the U.S. Chess Federation, were selected at random. They played against computers linked by telephone lines to their home bases.

A human problem kept Belle, the mechanical top-seed, from competing. Her computer operators were delayed by travel arrangements.

Belle was designed specifically for chess at Bell Laboratories in Murray Hill, N.J.

She has a rating of 2,150 points, or expert level. Last year, she was defeated by a master level player, a step above expert.