Arguments over the all-time greats in various sports rarely produce a consensus. Experts could wrangle endlessly without agreeing on the identity of history's best football player or basketball player or thoroughbred racehorse.

But in one sport such discussions now yield a unanimous conclusion. Virtually all of the knowledgeable people in harness racing concur that Niatross, who ended his career on Saturday night, was the greatest horse ever to pull a sulky.

Most would agree with Stan Bergstein, executive director of the Harness Tracks of America: "He is in a category different from all the other horses who have ever lived. It's as if we skipped a generation or two in the development of the standardbred."

Niatross' record has been remarkable. He won 38 of his 40 starts in two years of racing and, if he had been a little luckier, he might never have been defeated. He earned more money -- $2,019,212 -- than any standardbred ever has. He paced the fastest mile in history: 1:49 1/5 in a time trial. He paced the fastest mile ever recorded in competition: 1:52 1/5. He paced the fastest mile ever on a half mile track: 1:54 4/5.

Why did this particular individual develop into the supreme member of his species? When Secretariat achieved an almost comparable stature in the thoroughbred world, there was a reason. He was the product of the finest American bloodlines, the result of two centuries of "improving the breed." His physical construction was impeccable; one admirer of Secretariat's conformation said "it was as if God chose to make the perfect racehorse."

Niatross had no such credentials. Although he is the son of a great pacer, Albatross, the female line of his family tree is unimpressive. And while he is a big, good-looking colt, his conformation gave no clues that he would be a superhorse.

Niatross did show unmistakable brilliance when he won all 13 of his races as a 2-year-old, but this year his racing achievements were for a long time overshadowed by the controversy that surrounded him. His owner, his driver and the syndicate that controlled his future as a stallion were locked in acrimonious legal battles. Niatross' reputation was temporarily sullied when he fell and tumbled over the rail at Saratoga Raceway, then lost his next start at the Meadowlands. But as he finished his career with 18 straight victories, harness-racing fans savored his achievements, knowing they were witnessing a once-in-a-lifetime phenomenon.

No standardbred had achieved such fame since the legendary Dan Patch raced in the first decade of this century. But his achievements eclipse those of Dan Patch and the other mythic old-timer, Greyhound, as well as the great horses of the modern age, Bret Hanover and Albatross.

Don Evans, vice president of the U.S. Trotting Association and author of the biography of Bret Hanover, said, "It comes hard for me, but I'd have to say that Niatross is the greatest who ever lived. He had the speed and the consistency and a tremendous gait. Dan Patch may have been a bigger figure in the sport because he raced when the horse was king, but I don't think anybody except for a rare old buzzard would question that fact that Niatross was the best."

Jim Harrison, an author and former harness racing official, said, "I've been watching this sport for 50 years, and in my opinion Niatross lays over every horse I've ever seen. Some good horses can reach that extreme speed for a sixteenth or an eighth of a mile; you'd see them pull out at the top of the stretch and make their move. Niatross could do it at the half-mile pole and carry that speed for a half mile."

When Niatross ended his season with a victory at Pompano Park on Saturday, harness racing faced the same situation that thoroughbred racing did in the era of Secretariat. Because it is more profitable for a champion to breed than to race, the sport lost its greatest attraction; Niatross now will start his stud career at Castleton in Lexington, Ky.

After Secretariat retired, thoroughbred racing fans got to watch a succession of champions -- Seattle Slew, Affirmed, Spectacular Bid -- who almost made them forget about the greatest horse of the modern era. Harness racing aficionados can hope that Niatross' career similarly marked the beginning of a golden age, but it is unlikely that they ever will forget this extraordinary animal.