Seattle Slew was the first horse to achieve the feat before Justify repeated it in 2018. Seattle Slew went on to be defeated three times in 17 starts, while Justify retired unbeaten in six starts.

Read about Seattle Slew below in an article taken from ESPN.com

Seattle Slew exploded from humble beginnings

By Lisette Hilton
Special to ESPN.com

“[In the Kentucky Derby], here was Seattle Slew right next to me. I said, ‘Wow, this horse came in quick.’ And I look and there he was like this, looking at me. And I never noticed that on a horse. Seattle Slew passed me and took every other challenge from behind. And I said to myself, the horse is a champion,” says jockey Angel Cordero on ESPN Classic’s SportsCentury series.

From humble beginnings, Seattle Slew exploded into the forefront. Four years after the awesome Secretariat won the Kentucky Derby, Preakness and Belmont, Seattle Slew duplicated the feat in 1977. And he did Secretariat one better, by becoming the only undefeated Triple Crown champion.

In an era when it was common to see owners spend hundreds of thousands — even millions — on horses that they believed would reach Triple Crown status, Seattle Slew was purchased for a mere $17,500. As a colt, Slew didn’t look like the typical champion. But looks, it turns out, didn’t matter.

Two couples, the Taylors (Karen and Mickey) and Hills (Jim and Sally), bought him on July 19, 1975 at the Fasig-Tipton of Kentucky yearling sale in Lexington. Pointing to a horse with a big body and tiny tail, Hill, a veterinarian, said buy that one. Mickey, a fourth-generation logger, and Karen, a former stewardess, heeded the advice and the group went $2,500 over budget to purchase the horse — out of My Charmer by Bold Reasoning — that was born on Feb. 15, 1974 at Ben Castleman’s White Horse Acres in Lexington, Ky.

The new owners named their horse Seattle Slew because the Taylors lived near Seattle, Wash., and Hill came from Florida, a swampy, or “slewy” place.

One reason the horse was such a bargain was he was born with a right front foot that curved outward. He naturally swayed to the outside when he ran. Slew’s new owners turned the horse over to trainer Billy Turner, who found him so clumsy that he nicknamed him Baby Huey.

Turner changed his tune in the summer of 1976, when he took Seattle Slew to Saratoga to work out and discovered the horse once named after a clumsy duck cartoon character could run like the wind.

In his first race, a maiden at Belmont in September, Seattle Slew won by five lengths in 1:10 1/5. After winning an allowance race, his triumph in the Champagne States by 9¾ lengths earned him the Eclipse award as the top two-year-old colt.

Slew won his first three races in 1977 — two at Hialeah and the Wood Memorial at Aqueduct — before arriving in Churchill Downs as the first undefeated horse in the Kentucky Derby since Majestic Prince, who lost the Run for the Roses in 1969.

The fourth horse into the Derby gate, Slew was jittery before the start. When the gate shot up, a startled Slew lunged, stumbled and jerked his head sideways, cutting his mouth. It bled the entire race. The 13 other starters took off ahead of him.

Jockey Jean Cruguet steadied Seattle Slew and guided him strategically through the field. When Cruguet loosened his hold, the 1-2 favorite took off to win in 2:02 1/5, cruising home 1¾ lengths ahead of Run Dusty Run.

Seattle Slew’s next stop: Pimlico. A 2-5 favorite in the Preakness, he contended in an early duel with multiple stakes winner Cormorant before pulling away to win by 1½ lengths. His time for the one and three-sixteenths mile race was 1:54 2/5, only two-fifths of a second slower than Canonero II’s Preakness record.

Slew returned to New York for the Belmont Stakes. While nine other horses had won the Triple Crown, none had accomplished the feat without a loss. Seattle Slew quieted his naysayers and, just as in the Preakness, broke away from the start and stayed ahead. A 2-5 favorite again, Slew scored by four lengths over Run Dusty Run in 2:29 3/5.

The offers poured in for the first auction-bought horse to win the Triple Crown. Commercials for companies, including Xerox, featured Seattle Slew, as did T-shirts and other premium items. Some investors made offers as high as $14 million to buy the horse and racetracks enticed the owners with huge purses.

Fame began to unravel what had become known as the Slew Crew: the Taylors and Hills, Turner and Cruguet. Turner thought Seattle Slew needed rest and stood by his opinion. But three weeks after winning the Triple Crown, Slew raced again, as his owners were tempted by the $300,000 purse at the Swaps Stakes in Hollywood Park. Turner proved to be right. Slew wasn’t ready, and he suffered his first loss, finishing a disappointing fourth, 16 lengths behind winner J.O. Tobin.

Though Seattle Slew developed a bad cough and missed that year’s fall races, he was voted Horse of the Year and champion three-year-old male. He had won six of his seven starts and earned $641,370, tops in the country.

Despite the colt’s success, the Taylors and Hills were unhappy with Turner, who they thought was drinking too much, and they fired him several weeks before Christmas. Doug Peterson became Slew’s trainer.

The horse, who had recovered from his cough, took a turn for the worse in January 1978 in Florida. He stopped eating and sometimes broke into sweats, which lasted for hours. At times, he fell when he tried to stand. Hill diagnosed a viral infection and feared Slew might die.

But the horse recovered. Though weak, there was no question he would live and in February the Taylors and Hills sold a half-interest in him for $6 million, with George Layman Jr. being the principal investor.

In May, Seattle Slew competed for the first time in 10 months, winning an allowance race at Aqueduct. His owners soon set their sights on racing him against Affirmed, who that year won the Triple Crown. Never before had two Triple Crown winners met.

In September, Affirmed entered the Marlboro Cup at Belmont Park, a mile and an eighth race. Cruguet said Slew, who lost a tuneup race (the Paterson Handicap at the Meadowlands in New Jersey) to Dr. Patches, wasn’t ready for such a matchup. As a result, another of the original “crew” was ousted when the owners fired Cruguet and replaced him with Angel Cordero.

The 1-2 favorite, Affirmed had lost only once in nine starts. Seattle Slew, a 2-1 choice, broke first and stayed there into the homestretch. Affirmed came upon him for a moment before Slew poured it on to beat him by three lengths in 1:45 4/5.

Two weeks later, Slew won the Woodward Stakes over Exceller. Then in October, Slew and Affirmed met again, at the Jockey Club Gold Cup at Belmont. Both horses took off at a torrid pace, before Affirmed backed off when his saddle slipped. Meanwhile, Excellor blew by Slew to win by a nose.

Seattle Slew’s last race was an easy victory in the Stuyvesant Handicap in November at Aqueduct. He retired with 14 wins in 17 races and earnings of $1,208,726.

After Slew was voted the Eclipse for the Older Male Horse of the Year for 1978, he began life as a stud the next year at Spendthrift Farm in Lexington. His first crop included the outstanding two-year-old Landaluce and Grade I winners Adored, Slewpy and Slew o’ Gold. Later offspring included Swale, who won the 1984 Kentucky Derby and Belmont Stakes, and A.P. Indy, who went for $2.9 million, the highest paid for a yearling in 1990.

Elected to the Racing Hall of Fame in 1981, Slew was at Robert Clay’s Three Chimneys Farm in Kentucky from 1986 until going to Hill ‘n’ Dale Farm near Lexington in 2002. He sired 102 stakes winners.

In 1992, the original owners had a disagreement, and the Taylors bought out the Hills’ 25 percent share.

In April 2000, Seattle Slew was suffering from a neurological problem when he underwent surgery to fuse the joint between two vertebrae in his neck. Slew, who couldn’t walk before the operation, once again stood tall and he was returned to the breeding shed at Three Chimneys Farm in 2001.

But on May 7, 2002 — exactly 25 years to the day he won the Kentucky Derby — Seattle Slew died in his stall at Hill ‘n’ Dale Farm. He was 28.