Donald Cheska, who started riding on the international jumping circuit just one year ago, won the $5,000 Eisenhower Trophy on Southside last night at the Washington International Horse Show at Capital Centre, defeating a world-class field of 28 starters.

Cheska, 21, of Milwaukee completed the final round of seven jumps in 29:48 seconds. He was the fifth rider to go against the clock and had to come in trying to beat the time of 30:45 set by the first rider in the jump off, Mark Laskin on Damuraz, who eventually finished second.

Cheska said his strategy was to "keep the flow of the horse's stride steady and not shorten up around the corners. I was trying to ride as smooth around the turns as possible."

The win was not Cheska's most rewarding in his brief international career. "I won a class at the World Cup in Birmingham, England, last April," Cheska said. "I finished second and that was nice. What was nice about winning at Washington was watching all the best riders, probably 90 percent of the best international riders in the world, try to beat my time tonight."

Those who did try to go faster than Cheska included Melanie Smith, a United States equestrian team rider from Germantown, Tenn. Smith finished with a faster time (28:63) but had four faults because of a fallen fence.

Michael Matz of Plymouth Meeting, Pa., the reigning world champion after winning the overall title last April on his regular mount Jet Run, followed in the jump off. He, too, had a faster time (28:27) and he, too, knocked down the final obstacle.

Joe Fargis of Petersburg, Va., the final entry to go against the clock, finished with the fastest time of all on Touch of Class (26:82). He was also shut out at the last jump.

Katie Monahan rode around the course in an uneventful and conservative time of 32:54 without a fault, which made for a final score good enough to put the Upperville, Va., rider in third place