Racing purists usually bristle when a young horse is compared to greats of yore. Describing an up-and-coming colt as "the next Secretariat" is unforgivable, for there will never be another Secretariat. Mentioning a contemporary filly in the same breath with Ruffian is a comparable heresy.

But when a 2-year-old filly named Chilukki won her debut at Churchill Downs this spring, she astonished even fans with a proper historical perspective. It wasn't outlandish to suggest that she might indeed be the fastest, most precocious young filly since Ruffian.

Since her dazzling maiden victory, Chilukki has cruised to three straight stakes victories by an average margin of five lengths. No rival has ever been in front of her or given her a fight. When she runs in a stakes race at Del Mar Sunday, she is likely to steal the show from the older horses who are competing in the $1 million Pacific Classic.

Chilukki has won her last three races with so much energy in reserve that her times and margins of victory only hint at her potential. In her maiden race, however, she left nothing to the imagination when she exploded from the gate and trounced a field of well-regarded prospects by more than nine lengths. (Third-place Sweet Dixie, beaten by 14 lengths, subsequently placed in a stakes race; fourth-place Gilded Diablo, 15 lengths behind Chilukki, won a $75,000 stakes at Belmont Park.)

Chilukki sped 4 1/2 furlongs in 51 seconds flat, a time that won't resonate with racing fans because the distance is an uncommon one. But she shattered the Churchill Downs track record on a racing strip that wasn't exceptionally fast. The performance earned a Beyer Speed Figure of 109 -- better than any 2-year-old filly champion of the 1990s ever ran. It was the fastest debut by a 2-year-old since the colt Meadowlake in 1985. It may well have been the best debut by a 2-year-old filly since May 22, 1974, when Ruffian won by 15 lengths and equaled a track record at Belmont Park.

"She's a freak of nature," trainer Bob Baffert said of his filly, but he admitted that his admiration for Chilukki was not love at first sight. He saw the filly for the first time at a yearling sale, and wasn't impressed by the daughter of champion sprinter Cherokee Run. Baffert remembered that her half-brother was a cheap sprinter in California, and he isn't interested in buying sprinters.

But Chilukki was put up for sale again in February, at an auction of 2-year-olds in Florida, where the horses typically work a quarter mile and are judged on speed in addition to looks. "She was awesome. She was unbelievable," Baffert said. "She worked a quarter mile in :21 flat and galloped out [a half mile] in :46." Her precocity was no secret, and Baffert's client, Bob McNair of Stonerside Stud, had to spent $875,000 to acquire the youngster.

"I knew I was getting a really fast horse," Baffert said, but the trainer soon discovered that Chilukki has many other virtues. She has the relaxed temperament that all trainers love; visitors to the Baffert barn can pet her as if she were a docile stable pony. And she has an economy of motion that makes her an efficient runner. Baffert said, "It's unbelievable how effortlessly she does everything. When I look at my watch [after a fast workout] I say, `How can she do it?' The great ones are that way."

Chilukki hasn't had to run exceptionally fast to win her last three starts, and she'll probably cruise to another easy victory against her overmatched foes in Sunday's seven-furlong Del Mar Debutante Stakes.

The first real test for Chilukki will come when she attempts to run beyond a mile -- in the Alcibiades Stakes at Keeneland in October and then in the Breeders' Cup Juvenile Fillies in November. Even though Baffert once dismissed her as a mere sprinter, he believes now that her combination of speed and tractability will make her an effective distance runner. "I've already had her work a mile," the trainer said. "Going around two turns will not be a problem for her."

It is possible that Chilukki could go through her entire 2-year-old season undefeated and unchallenged, because there doesn't appear to be any other horses of her age and sex capable of pressing her. But racing fans would like to see more than a perfect season; we'd like to see her go full-throttle and show just how fast she is.

After Ruffian had displayed brilliant speed early in her career, she coasted to a series of easy victories that gave no real indication of her real talent. Undefeated, she was to get her first great test in her match race with Foolish Pleasure; when she broke her leg, it was one of the sport's most poignant tragedies and it left her great promise unfulfilled.

Perhaps Chilukki is a mere sprinter. Perhaps her smashing debut was an aberration. But racing fans surely hope that she will get the opportunity denied to Ruffian: to show just how good she is.