I'm in love with a filly.

Her name is Companionship, and although she has not yet won a major race, she probably is the best 2-year-old filly in America. In fact, she has displayed such virtues in her brief career that she may be the most admirable 2-year-old legendary Ruffian.

In the eighth race at Saratoga on Monday, the $50,000 Adirondack Stakes, Companionship figures to achieve her first important victory. But it is hard logic -- not sentiment -- that makes her a solid bet.

Companionship made her racing debut on July 18 at Belmont Park, and needed only 21 3/5 seconds to demonstrate that she is something special.

That is the time it took her to cover the first quarter mile of a six-furlong maiden race, even though she had broken from the disadvantages inside post position and was racing on the deepest part of the track. Few race trackes could remember the last time a horse had shown such speed at Belmont. By contrast, a group of tough older male sprinters, competing in the True North Handicap over a faster racing strip, had gone the first quarter in 22 2/5.

After Companionship had sped a half mile in 45 seconds flat, she was challenged by Smiling Sera, a highly promising first-time starter who was the even-money favorite. Anybody would have expected the leader to collapse after her early exertions. Companionship didn't. When Smiling Sera took a slight lead, Companionship battled back with ferocity and managed to finish in a dead heat. c

That performance encouraged trainer Guillermo Barrera to enter Companionship in the opening-day Schuylerville Stakes here. This time she had the misfortune to be entered against another speedball, Famous Partner. The two of them battled through a quarter mile in an incredible 21 2/5 seconds and a half in 44 2/5, a duel so enervating that Famous Partner fell apart and finished last by 31 lengths. But Companionship kept running.

When Sweet Revenge made a powerful move on the turn, drew abreast and looked as if she were going to run with the race, Companionship refused to let her pass. She was holding off her challenger when jockey Ruben Hernandez chose an inopportune time to drop his whip. In the last eighth of a mile, Hernandez could only slap Companionship on the neck with the palm of his hand, and the filly lost by a neck.

It is obviously a chancy thing to predict future greatness for a horse after only two races. She is in the hands of a trainer who has long been overshadowed by his illustrious brother,Laz Barrera, and who has never won a stakes race in New York.

Championship's bloodlines are obscure, and do not provide any guarnatee that she will want to run farther than three-quarters of a mile. But any horse who combines such raw speed with such competitiveness, such heart, has the potential for greatness.

If Companionship's long-term future is difficult to predict, her short-term furture is easy. She ought to win today's race with authority. After encountering tough conditions in her first two races, she seems to have the deck stacked in her favor today.

The inside part of the Saratoga racing strip has been extremely advantageous in the last few days, and has given a significant edge to front runners. The track bias has been so powerful that it enabled a faint-hearted sprinter, Love Sign, to win at 1 1/4 miles in the Alabama Stakes on Saturday.

In the Adirondack field there are no fillies who can prevent Companionship from getting to the lead and to the rail. Sweet Revenge is meeting her again, but the time the track will hinder the stretch-runner. After today, the racing world will know how good Companionship is.