ESPN Horse Racing

LOUISVILLE, Ky. -- Mike Smith's knees buckled at the wire. His strength left him. He endured a literal backbreaker seven years ago and several heartbreakers on Kentucky Derby day -- but the greatest thrill of his career was nearly too much to handle.

"I was just hanging on for dear life," Smith said.

The steed he was hanging onto was Giacomo, merely the most unlikely Derby winner in the last 82 years. It's been that long since Donerail won the roses at 91-1 in 1913. At 50-1, Giacomo barges preposterously into the record books as the second-longest shot to win in the 131-year history of the race.

If you're looking for a comparison, picture Idaho winning the Fiesta Bowl.

A Kentucky Derby victory was a long time coming for jockey Mike Smith.

But the winner was only the beginning of the absurdity. Behind Giacomo came a veritable cavalry charge of Who's That -- runner-up Closing Argument at 72-1, fourth-place Don't Get Mad at 29-1, fifth-place Buzzards Bay at 46-1 and sixth-place Wilko at 22-1. Afleet Alex, who finished third after taking the lead briefly in the final sixteenth of a mile, was the only horse among the top six at odds of less than 20-1.

The result -- Powerball payouts on exotic wagers. The exacta paid a Derby-record $9,815. The trifecta was a Derby-record $133,135. The superfecta from a $2 wager was a Derby-record -- and scarcely believable -- $1.7 million.

An hour after this inconceivable result, Smith himself held a wrinkled mutuel ticket in his hands -- $200 to win on Giacomo, given to him by the colt's owner, Jerome Moss. That's worth a cool $10,200 -- if Smith decides to cash it. He might frame it instead, because this win was worth more than money can buy.

The Derby gods have taken their pound of flesh from Smith over the years. He'd had 11 mounts in the race and finished second three times. During the mid-'90s, he was aboard the favorite three times in four years -- and three times he watched another jockey exult at the wire. The best of those three favorites was Holy Bull, a powerful colt who had the worst race of his career when it counted, breaking badly and finishing 12th in 1994.

In a fine twist of fate, Smith won his first Derby on Saturday aboard Holy Bull's son, while wearing a Holy Bull T-shirt under his flak jacket -- in a result that bordered on the absurd.

"I felt the lowest you could feel in the Derby," Smith said. "Now I feel the highest."

Between the lows and the high came an accident in 1998 that nearly ended Smith's career. He was bumped into the hedge one race at Saratoga, fell off his mount and had the horse somersault onto him. The result -- a broken back.

What does it feel like to have a 1,100-pound animal fall on you?

"It hurts," Smith said, "really bad."

But Smith wanted to ride again and pushed his rehab to make the '99 Kentucky Derby and ride Cat Thief for D. Wayne Lukas. Probably pushed it too hard.

"I probably came back five months too soon," Smith said. "My doctor told me that, but I was so bull-headed. I wanted to ride in the Derby so bad."

Smith estimates that it took a good year before he was back to full strength. Many in the racing business believe it took even longer than that to regain that crucial riding quality -- nerve.

"I'd be lying if I said there weren't times when you think about it," Smith said.

Today, however, Smith is riding like the guy who reached the top of his profession a decade earlier. And Saturday was one of his finest rides.

As expected, the pace of this Derby was wicked, which set up the race nicely for Giacomo's grinding, come-from-behind style. Smith took his horse to the back of the pack the first time past the grandstand but then had to make a bold move heading into the first turn by swinging outside another horse -- jumping over the other colt's heels.

"He was going to take me into the tents on the far side," Smith said. "I had to make a drastic move that ended up saving me two or three lengths when it could have cost me two or three lengths. We would've lost the race."

From that point on, Smith was content to roll along near the very back of the pack -- Giacomo was 18th after ¾ of a mile. Before heading into the far turn, he finally asked the horse for his run, and Giacomo inexorably began moving past his tiring competitors.

As the front-runners fell apart heading into the stretch, Smith still had much work to do. He had to duck Giacomo in and out of traffic, finally finding daylight near the middle of the track. As Afleet Alex shortened up near the wire, Smith's colt strode past and beat Closing Argument by half a length in the final jumps. The only jockey Giacomo has ever had booted him to only his second career victory -- in the biggest race he'll ever run.

Recovering from the shock, Smith pumped his fist and blew kisses to the crowd after bringing Giacomo back on the way to the winner's circle. As the roses were draped on the horse's back, a little boy stood nearby with a wide smile on his face.

"I loved this horse since last year," said Jose Santos Jr., son of the 1994 Derby-winning jockey.

Clearly, it took a 10-year-old's point of view to see this one coming.

As Smith began walking back through the grandstand, a large man came forward to embrace him -- none other than former NFL linebacker Bryan Cox, a friend of Smith's for the last 10 years. The odd couple was just another fittingly odd element to this Kentucky Derby.

Smith was besieged by autograph seekers walking back to the jocks' room and did his best to accommodate them all. Everyone was happy for the 39-year-old -- even his competitors. John Velazquez, fresh off a horribly disappointing 19th-place finish aboard Bandini, grabbed Smith's head with two hands and kissed it. Gary Stevens, a three-time Derby winner who finished 14th this time aboard Noble Causeway, kissed Smith on the cheek and hugged him tightly.

At Philadelphia Park, where they were undoubtedly rooting this year for Afleet Alex as they did last year for Smarty Jones, there was at least one happy man in the house. Mike's dad, George, gallops horses there in the mornings and parks cars in the afternoons.

Last year he was the only one at Philly Park rooting for the runner-up, Lion Heart, ridden by his son. This year, he got to see Mike finally get his Derby.

"My dad was in the bathroom getting sick the whole race, I guarantee it," Smith said. "But he'll watch the replays."

So will Mike. He'll see a brilliant ride aboard the longest Derby shot he's ever ridden, and he'll see a shockingly happy ending.

"I was proud of myself today," Smith said, smiling. "I did good."

Pat Forde is a senior writer for ESPN.com.

Watch the Preakness Stakes on Saturday, May 21 at 5 p.m. ET on NBC.