Major stakes races for 3-year-olds were run in New York, New Jersey and Arkansas on Saturday, and they sharply altered the outlook for the Kentucky Derby.

This is the time of year when Derby-age horses sometimes seem to mature suddenly and improve overnight, and two of them did it in dramatic fashion -- Spend A Buck with his victory in the Garden State Stakes, and Tank's Prospect with his triumph in the Arkansas Derby.

Both colts had been ranked among the top of their generation last year, but neither had displayed any great brilliance.

Spend A Buck always had looked as if he basically was a miler, but he corrected that impression with an astonishing performance at Garden State. He ran 1 1/8 miles in 1:45 4/5, equaling the fastest time run at that distance around two turns, and missing Secretariat's world record (set on the one-turn course at Belmont Park) by two-fifths of a second.

Spend A Buck had everything his way in the race. With virtually no other speed in the field and jockey Angel Cordero Jr. in the irons, he was able to take a commanding lead. Even so, this was one of the more overpowering prep races ever run before the Kentucky Derby, and Spend A Buck will be a major factor in Louisville.

"This horse is getting better every time he races," trainer Cam Gamboletti said. "I am glad he was able to relax going around two turns."

Tank's Prospect virtually had been written off as a Derby contender when he finished last in the Santa Anita Derby. But trainer Wayne Lukas attributed the colt's loss to a throat problem: a swollen membrane was restricting his breathing. Last week, Tank's Prospect underwent surgery to correct the problem. Lukas shipped the colt to Oaklawn Park in Arkansas a few days later -- hardly a conventional way to prepare for a $500,000 race -- and maintained Tank's Prospect was ready to deliver a top performance.

He was right. Tank's Prospect ran the best race of his life as he swept to a six-length victory in the Arkansas Derby. The opposition was weak, but Tank's Prospect finished powerfully and his time was excellent -- a couple of lengths better, in fact, than Eternal Prince's performance in the Wood Memorial Stakes, which had looked on paper to be the strongest of Saturday's Derby prep races.

Eternal Prince led all the way, but his performance was not nearly as impressive as his victory in the one-mile Gotham Stakes two weeks earlier. His effectiveness might decline as the distances get longer, and the 1 1/4 miles of the Kentucky Derby could prove too far for him -- especially if he has to cope with the speed of Spend A Buck.

Highly regarded Rhoman Rule finished five lengths behind Eternal Prince in the Wood, but he came out of the race looking like a better Derby contender than the winner. Trainer Angel Penna Jr. and jockey Jacinto Vasquez clearly had decided to treat the Wood strictly as a prep race. Vasquez was content to let Eternal Prince steal off to an easy lead. In fact, he restrained Rhoman Rule so much that he was behind plodding Proud Truth in the early stages.

Rhoman Rule, Tank's Prospect and Spend A Buck must be considered the leading candidates for the Derby. Chief's Crown will join the list, assuming he wins his final prep, the Blue Grass Stakes at Keeneland Thursday, as is expected. Proud Truth, Eternal Prince and Stephan's Odyssey -- the winner of the Lexington Stakes at Keeneland -- also are contenders.

Saturday's stakes not only changed the list of the probable Derby favorites, but also altered a widespread perception of this whole generation. This has appeared to be an extraordinarily weak crop of 3-year-olds, but the performances by Tank's Prospect and Spend A Buck were solid ones. Noboby is going to win this Kentucky Derby by default.