The French Equestrian team scored its second victory in as many days at the Washington International Horse Show last night at Capital Centre as Michel Robert rode Pequignet Lafayette to win the International Open Jumper Class Eisenhower Trophy.

France took the lead in the team competition with 21 points. The United States and Canada have yet to score in that competition.

Robert, 38, defeated Katie Monahan Prudent of Middleburg and 31 other competitors in the $10,000 event. Nine entries completed the first round of the 13-fence course without incurring any faults to advance to the speed jumpoff round.

Four of those finalists finished that round perfectly, but Robert finished with the fastest time, 31.40 seconds. Monahan Prudent, the 1986 rider of the year, made her second attempt immediately before Robert, finishing in 33:09.

Robert, who has represented France in international competition for 15 years, pushed his 10-year-old gelding hard to score the faster finish.

"I had to take a lot of risk in this class," he said. "Katie, with Special Envoy, is very, very {fast}. The jumpoff was difficult. In Europe, there are rarely two combinations in the jumpoff. I took a risk at every fence."

Monahan Prudent has two top horses to show this week. Special Envoy has been doing well lately, as has Make My Day. Her goal throughout the week is to determine the best mount for the $40,000 President's Cup Grand Prix on Sunday.

Michaela Murphy, in the lead for national rider honors with seven points, placed third on Gusty Monroe. The 23-year-old Far Hills, N.J., resident rode the 7-year-old brown gelding through two faultless rounds, the second in 35:20.

The French team, which leads in the race for the coveted Gucci Cup in the Nations' Cup series, proved it will be a strong competitor to the U.S. team in the team event here Thursday. The U.S. team will try for its ninth consecutive win in the show's Nations' Cup then.

In the International Hunter Futurity class, Scho Biz, ridden by Patty Johnson, won the championship ribbon in the over fences category. Joe's Milestone, ridden by Patricia Heukeroth, won the under saddle class.

The show continues today with the hunter classes and championships. This evening features the ladies side saddle competition and the $10,000 International Open Jumper Gamblers Stake, in which riders jump fences of their choice for points based on difficulty.