Michael Matz guided Jet Run, who once ran in $1,200 claiming competition at Charles Town, to victory in the $25,000 Anheuser-Busch President's Cup Grand Prix last night in the final event at the Washington International Horse Show.

The $7,500 first-place money was $7,500 more than the 12-year-old bay gelding ever won in his undistinguished career as a race horse. He now is owned by F. Eugene Dixon of Philadelphia, who also owns the Philadelphia 76ers basketball team.

As a racehorse once owned by Allen Jenkins of Orange, Va., Jet Run was "at the bottom of the bucket," according to one family member. In his last race as a $1,200 claimer, he finished dead last.

Last night, in front of 6,272 fans at Capital Centre, Jet Run had speed to spare, finishing the eight-jump course in 32 seconds. Second-place finisher Gilles Bertran de Ballanda of France was timed in 35.82 on Galloubet A.

The United States won the international team title with 75 points, Barney Ward of Brewster, N.Y., took home the National Rider award and Bertran won the International Rider title.

Jet Run was first converted into a show jumper when America's best show rider, Rodney Jenkins, brought him home to the farm and taught him how to jump. By the time Dixon bought the horse, his value had skyrocketed to a reported $300,000 purchase price.

Matz was one of eight riders to advance to the final jump-off against the clock following two grueling rounds of competition. He led off the jump-off.

Matz, a member of the United State equestrian team riding unattached, had won only one Grand Prix this year, at Lake Placid, and finished second in three others. "All summer long I kept having one pole down here and there," Matz said.

Galloubet A was the last horse in the jump-off. "I couldn't go quicker than Jet Run," Bartran said. "After the first turn I saw I wouldn't be able to do a better time, so I made the choice to be second."

Matz said when you are in "a timed jump-off you have to try to put enough pressure on so they have to go just as fast. And you hope they'll make a mistake."

With attendence at an all-time record for the eight-day show, officials are even more optimistic than when it was reported this might be the final year for the 22-year-old event. David Lamb, vice president for administration, said "There is every indication that we will be back at the Capital Centre next year."