For a jockey who had become thoroughly discouraged, had retired and started to learn a new way to earn a living, Greg Smith didn't have a bad day Saturday.

The 24-year-old rode Mighty Appealing to victory in the $292,475 Laurel Futurity and he rode him brilliantly. The colt might not have won at all if Smith had not been so patient, so cool, so tactically astute.

Naturally, Smith was exuberant after the biggest payday of his life. But he also had to worry that this might be the triumph that comes before a fall, that he could be headed for the second devastating, demoralizing blow of his brief career.

Like any would-be jockey, Smith had dreamed of handling top-class stakes horses such as Mighty Appealing when he started to ride four years ago. Unlike most youngsters, he got his chance quickly. After growing up near Baltimore and working on a Maryland horse farm, he came to the track under the tutelage of the veteran trainer Henry Clark.

His timing could not have been better. When he was starting to ride regularly for Clark, the stable had an unraced colt named Linkage. Smith rode him in his debut, and proceeded to score six victories in eight starts that established Linkage as one of the best horses of his generation. Smith was beginning to entertain visions of the Triple Crown races, but when he finished second in the Louisiana Derby, Clark decided to make a change. Exit Greg Smith, enter Bill Shoemaker.

Even though he should have expected to be bumped in favor of a big-name rider, Smith was crushed. And when he came back to Maryland after spending the winter in Louisiana with Clark and Linkage, his whole career seemed to be crushed.

"When I had left Maryland I'd been the fourth-leading rider," he said. "But when I came back there were articles in the paper saying the owner had wanted a stronger rider for Linkage. A lot of people wondered why I'd been taken off the horse and thought something must be behind it. My business started to fall apart."

For the next year, it never got much better. Having ridden one of the best horses in America, Smith found it depressing to scramble and beg for mounts on cheap claimers.

In the summer of 1983, he gave up and took a six-month vacation from the track -- skiing, visiting the Florida Keys, relaxing, pondering his options. He finally concluded that he wanted to stay in racing but didn't want to pursue his career as a jockey.

So he went to work as an exercise boy in the mornings, and got a part-time job with the film patrol at the Maryland tracks. He operated cameras that provide film coverage of the races for the stewards and the closed-circuit television.

He would get up at 4:30 in the morning, gallop horses for trainer Dean Gaudet until 10 a.m., then work the cameras from noon to 5. It was a tough schedule, but Smith was content, until Mighty Appealing came along to alter his regimen and his life.

Smith had been impressed by the precocity of the unraced colt as he galloped him and worked him this summer. The 2-year-old was scheduled to make his racing debut on opening day at Laurel, and Smith might well have been watching that race through one of the film-patrol cameras, except that Gaudet's regular jockey, Dave Byrnes, was sidelined with a suspension at the time.

"You've worked this horse," Gaudet told Smith. "Would you be interested in riding him?"

"I'd have been a fool to turn her down," Smith said. "I went right home to get my tack."

Smith piloted Mighty Appealing to a 16-length win in his maiden race and a nine-length victory in his second start. Any jockey capable of holding on to the horse could have won those races, but Gaudet didn't want to make a change when she entered her colt in the Futurity.

Gaudet could easily have been criticized or second-guessed for using an unseasoned rider in a big field with so much money at stake, but Smith justified the trainer's confidence in him.

When Mighty Appealing failed to break sharply for the first time in his life, Smith let the colt relax, worked his way through heavy traffic and got to the rail. He saved ground all the way around the turn while his rivals were going wide or getting into trouble, drove inside the leaders as he entered the stretch and scored a 2 1/2-length victory that established Mighty Appealing as one of the best 2-year-olds in America.

It was the sort of implausible twist of fortune that every struggling jockey dreams of. Smith said, "You don't know how many riders have come up to me and said how discouraged they are and how this shows that anything can happen. It's a Cinderella story."

But in Cinderella stories, the clock inevitably strikes midnight and the protagonist is left without a chariot. It is a hard fact of life in the racing world that lesser-known jockeys who ride champion racehorses are eventually replaced by jockeys with loftier credentials. (Remember Ron Franklin on Spectacular Bid? Rudy Turcotte on Cure the Blues? Greg Smith on Linkage?)

Now that Mighty Appealing has suddenly acquired a national reputation, plenty of jockeys with national reputations are going to be aiming their daggers at Smith's back.

"I think about that," Smith conceded, "but we have an agreement and as long as Mighty Appealing keeps running well I think Miss Dean is going to continue to ride me. I fit the horse so good and we get along so good. But if I make a blatant error . . . "

After his experience with Linkage, Smith knows all too well what could happen next.