LEXINGTON, Ky. - Dominican by a nose, Curlin in a rout.

In little more than an hour Saturday afternoon, the results of two races scrambled the field for the Kentucky Derby.

Street Sense, considered the early Derby favorite, was nosed out at the wire by long-shot Dominican in the Blue Grass Stakes at Keeneland. Despite a gallant effort by the Breeders’ Cup Juvenile winner, Street Sense no longer has an air of invincibility and dropped to No. 3 in this week’s Run to the Roses’ Top 10.

Then along came Curlin, who produced a dazzling 10½-length win in the Arkansas Derby at Oaklawn Park. The rising star who did not run as a 2-year-old is 3-for-3 — by a combined 28½ lengths — and may be the most exciting Derby contender of all.

The last horse to win the Derby with just three stars was the filly Regret in 1915; the last Derby winner who did not race as a 2-year-old was Apollo in 1882.

Even so, Curlin soars into the Top 10 for the first time at No.

4. Trainer Steve Asmussen, 0-for-5 in the Derby, expects his latest contender to be the favorite.

“I’d be very surprised if he wasn’t the favorite going in,” the trainer said. “He’s beating them easy, and everybody loves that.”

Curlin was the 7-2 Derby future wager favorite after final betting closed Sunday.

Curlin was purchased for a reported $3 million for a partnership that includes Stonestreet Stables, Padua Stables, George Bolton and Midnight Cry Stables. The colt won the Rebel Stakes by 5¼ lengths in his second start after breaking his maiden by 12¾ lengths at Gulfstream Park on Feb. 3.

Arkansas Derby winners have fared well in Triple Crown races recently — Smarty Jones won the 2004 Derby, and Preakness and Afleet Alex won the 2005 Preakness and Belmont Stakes.

Dominican, named for the order of nuns who run St. Catherine College in Springfield, Ky., also moves into the Derby picture — at No. 10.

The gelding staged a thrilling rally in the stretch and caught Street Sense in the final stride, with Zanjero a head back in third and Teuflesberg another head back in fourth.

“We wanted to go the Derby and we needed to see if we could hook them,” Dominican’s trainer Darrin Miller said.

Hook ’em? He beat ’em, and with the winner’s share of $465,000 there are no worries Dominican would be left out of the Derby if more than 20 horses are entered and graded-stakes earnings decide who runs.

Dominican’s three wins have come on Polytrack. Can he win in the dirt at Churchill Downs on May 5?

“I think he can run on anything,” Miller said.

Wood Memorial winner Nobiz Like Shobiz remained No. 1 this week, with Florida Derby winner Scat Daddy moving up to No. 2.

Trainer Doug O’Neill had a tough weekend. He was unable to make it to the Blue Grass, but watched on TV from California as Great Hunter finished fifth. Earlier in the day, his Florida Derby runner-up Notional was knocked off the Derby trail with an ankle injury in a morning gallop at Churchill Downs.

Great Hunter is still headed to the Derby, O’Neill said Sunday, meaning the top Blue Grass finishers are headed to Churchill Downs.

“We’ll just keep going,” O’Neill said. The trainer has two other Derby contenders in Cobalt Blue and Liquidity.

Meanwhile, trainer Todd Pletcher is planning on a record-equaling five Derby starters — Scat Daddy, Circular Quay, Cowtown Cat, Any Given Saturday and Sam P.

Lane’s End Stakes winner Hard Spun had a sharp workout at Churchill Downs on Thursday, and was declared a go for the Derby. The colt trained by Larry Jones has five wins in six starts.

Dropping out of the Top 10 were Notional and Cowtown Cat.