As Caveat started to accelerate on the rail this afternoon, the Belmont Stakes was transformed into a game of inches.

Jockey Laffit Pincay Jr. saw two horses ahead of him, Slew o' Gold and Au Point. He also saw that the space between Au Point and the rail was approximately equal to one horse width--give or take a few millimeters.

Angel Cordero Jr., riding Slew o' Gold, didn't become one of the two greatest jockeys in the United States by reacting docilely in such circumstances. He inched closer to Au Point, whose jockey, Gregg McCarron, said, "He was trying to force me over and shut the hole off." The opening shrunk by a few more millimeters.

But Pincay did not become the other one of those two greatest jockeys by hesitating in such circumstances. He urged his mount forward, hugging the rail and getting jostled, but when Caveat drove through that narrow hole the 115th running of this classic was as good as over. Caveat drove to a decisive 3 1/2-length victory over Slew o' Gold, becoming the first Maryland-bred winner of this race in more than a century.

Barberstown was third and Deputed Testamony, the Preakness winner, finished sixth.

Caveat ran the 1 1/2 miles in a very respectable 2:27 4/5, a time that did not support the widespread conviction that this 15-horse field was extraordinarily weak. Certainly, Caveat's credentials were not especially impressive--he had never won a major stake before--but the bettors here made him the virtual cofavorite because they thought his stretch running style would be perfectly suited to this demanding distance. They were right.

Trainer Woody Stephens, who had teamed with Pincay to win this race with Conquistador Cielo last year, told his jockey before the race to take Caveat far back and make one big late run. At first Pincay was having a little trouble. "In the first 16th of a mile," he said, "he was wanting to run too much." But Caveat finally started to relax and to retreat, while on the front end the Belmont developed as expected.

Au Point opened a four-length lead, as Slew o' Gold stalked him. The leader was setting an honest pace--a half-mile in :47 2/5, six furlongs in 1:11 3/5--while Caveat dropped to 12th place.

Entering the final turn, Cordero swung outside Au Point, and probably expected to accelerate quickly past that lightly raced, lightly regarded colt. But Au Point was fighting back. They raced together around the turn, as Caveat was starting to accelerate, many lengths behind them.

"A couple of times I thought about going around horses," Pincay said, "but there was no way." In the congested field--the biggest in Belmont history--he was committed to staying on the rail, where his presence created a potentially explosive and controversial situation.

The stewards posted the inquiry sign, but Pincay was smiling as he was led into the winner's circle. He knew he had been a victim, not the aggressor, and said he would have claimed foul himself if Slew O' Gold had beaten him. "The other horse came in and put me into the fence," Pincay said.

The stewards concluded there was no reason for any disqualification. They said in a statement: "Although there was bumping, at worst it could have been a 50-50 proposition, with Au Point contributing to it."

When the official sign went on, Caveat paid $7.20, $3.60, $3.40. Slew O' Gold returned $4.60 and $4.40. Barberstown, who narrowly beat Megaturn for third, paid $4.80 to show.

Caveat races in the name and colors of August Belmont IV, whose great grandfather built this track, but is also owned by two other partners, Jim Ryan and Bob Kirkham. Ryan bred him on his Ryehill Farm near Mount Airy, Md., and thought last year that he had bred a very good grass horse. But that seemed to be all Caveat was good at: he lost his first 12 races on the dirt.

This spring, however, he began to display some versatility. He won the Derby Trial at Churchill Downs, then rallied from 17th place to be third in the Kentucky Derby. When he saw that fast finish, Woody Stephens started to think that Caveat was a Belmont horse. And as soon as he saw Pincay squeeze through that little hole in the turn, he knew he was right.