Two summers ago, Paul Cornman came home from a day at the races at Saratoga and announced to his roommate: "There was a horse who ran today that I want to buy."

Cornman had never owned a thoroughbred before. Moreover, his only income came from betting the horses and his bankroll happened to be somewhat meager at the time. But he had been so impressed by the two-length victory of a gelding named Win over a nondescript field of New York-bred allowance horses that he was prepared to invest virtually all his resources to get him.

The virtues Cornman saw in the 3-year-old weren't glaringly obvious, even to people who consider themselves ace handicappers. I was his roommate that summer. I did not reach for my checkbook and say, "Paul, go buy him. I'm your partner."

A number of Cornman's other racetrack pals were similarly unconvinced, and they are similarly kicking themselves, because Win has gone on to earn more than $1.2 million since the summer of '83.

He is such a consistent and talented grass runner that he will be favored against a strong field if he runs in Saturday's $400,000 Washington, D.C. International at Laurel.

Cornman managed to scrape up enough capital to buy one-third of the gelding from owner-trainer Sally Baillie.

Fred Ephraim, a clinical psychologist from New York, independently bought a one-third interest at the same time. Baillie kept the rest. Under their tripartite ownership, Win has made them all look like geniuses.

"The reason I liked Win was the way he acted when he started to run on the grass," Cornman said. "On the dirt, he had all the wrong habits: he was bad at the gate, he lugged in, he had a nonwinning attitude. But when he got on the turf, he made the transition from a rogue to a professional; he got his head together. And he had a nice kind of motion on the turf -- a different way of running. I thought he could do well in stakes for New York-breds or in high-priced claimers."

Not even the most wild-eyed optimist could imagine that Win would keep improvng so much that he could beat the best turf horses in the world. For this, the credit goes to Baillie, one of the few women in the major leagues of the training profession.

"Sally's patience was the key," Cornman said. "A lot of guys get a horse like Win and they feel pressure to get fast results. They never give the horse time to mature. Sally gave Win all the time he needed."

By the end of his 3-year-old season, Win was good enough to leave New York-bred company and capture an open stakes races. As a 4-year-old, he won three stakes and lost a photo-finish decision to the legendary John Henry. This year, he has won three stakes in New York and is a prime candidate for the Eclipse Award as the country's champion grass runner.

His main obstacle in the International is likely to be the condition of Laurel's grass course rather than any of his 13 prospective rivals. Win doesn't like soft turf, and he won't run Saturday if the course is too mushy. Baillie intends to gallop him over it today or Thursday before making a decision.

Regardless of what happens at Laurel this week, Win could very well go on to be another John Henry. He's a gelding, he's sound and durable and, so far, he has been improving with age. He also has the same combination of versatility and competitive spirit that made John Henry an American institution.

If racing fans can admire Win's achievements, hard-core bettors will identify with Cornman's. He has been playing the horses all his life, and even in the jealous little world of the race track, his handicapping expertise commands the respect of everybody who knows him. Like most gamblers, he has endured his share of lean times, but he has never had to work a 9-to-5 job, and after Win, he probably never will.

In the wake of Win's success, Cornman has made two more horse purchases based on his handicapping insights. One was a disappointment, but the other was a colt named Exclusive Partner. Cornman acquired him after he won a $45,000 claiming race by a half-length. In the next three months, he won or placed in four stakes.

Cornman probably will be the only owner at the International who can say that two-thirds of his stable consists of stakes horses, but he still doesn't identify with the high society in the Turf Club. Most of them have horses in the race because they're very wealthy and they can afford to buy the best bloodstock.

If Cornman gets to the winner's circle Saturday, it will be because of the years he has spent in the grandstands of the New York tracks, watching races and studying the racing form.