Gold River, a 36-to-1 shot ridden by Australian Gary Moore, was the surprise winner of the $618,000 renowned Prix de l'Arc de Triomphe, the richest horse race in Europe, at Longchamp race track in Paris yesterday.

Another unheralded horse, Bikala, ridden by Serge Gorli, came in second, edging third-place April Run, with Philippe Paquet aboard, in a photo finish.

Gold River's trainer, Abe Head, thus scored his fourth Arc victory. The 4-year-old filly also won the Prix de Cadran in May. Gold River earned $360,000 for her win.

Moore's father, George Moore, won the Arc de Triomphe in 1959, riding Saint Crespin.

The two favorites, Detroit and Akarad, finished out of the money.

Martina Navratilova brought Tracy Austin's 28-match winning streak to an abrupt halt last night by winning the $125,000 U.S. Women's Indoor tennis championships, 6-0, 6-2, at the Met Sports Center in Bloomington, Minn.

Navratilova broke Austin's service six times to extract a measure of revenge for last month's three-set loss to Austin in the final of the U.S. Open.

Navratilova picked up a $22,000 first-place check for the match, which lasted only 51 minutes. That brought her yearly earnings to more than $477,000. It also was the seventh tournament victory for Navratilova this year, but her first since May, when she won the Tournament of Champions in Orlando, Fla.