Tyler Hamilton has revealed his Olympic gold medal inspired him to go for glory in the Tour of Spain.
Hamilton defied a back injury to win Olympic gold
Hamilton has only once competed in the third Grand Tour of the season - in 1999 - and struggled throughout.
But after winning gold in the time trial in Athens, he told BBC Sport: "I'd had no plans to go for the Vuelta - my sole focus was the Olympics.
"But after getting that gold, it gave me such a boost. I could either take it easy or go to the Vuelta."
The American Phonak rider, a former team-mate of Lance Armstrong, had arrived at the Olympics with a back injury.
The complaint, picked up in a crash at the Tour, was still hampering Hamilton when he lined up against the clock in Athens.
But Hamilton said: "It's amazing how strong a painkiller the lure of gold can be. It was still hurting but I was not far off from being 100% when I got going.
"As for winning gold, that was something else. I'd always dreamed of being an Olympian [initially in his first love as an alpine skier before a horrific crash]. But to stand with a gold around my neck was almost too much to take.
"Added to that, there are a lot of people who don't know about the Tour de France [cycling's blue-riband event] but everyone knows about the Olympics.
"So to suddenly have Olympic gold was a dream come true."
Having put all his attentions after the Tour into preparing for the Olympic time trial, Hamilton admits he may not be in the right form for the Vuelta, which got under way on Saturday.
"An hour on the bike's a lot different, from three weeks almost non-stop in the saddle," he said. "But I'll just see how we go.
"I'm in this race to win it but I guess I've got the excuses in place nice and early!"
Hamilton faces stiff opposition from defending champion Roberto Heras, Alexandre Vinokourov and Alejandro Valverde, as well as the American's own team-mate Oscar Sevilla.
"In fact, I'm not even our team leader in this one," he said. "That rests with Oscar this time so the pressure's well and truly off."
Despite downplaying his chances, Hamilton is arguably the most talented overall bike rider in this year's race, a superb time triallist and a solid climber.
Added to that, he arguably has more determination than any of his peers.
A year ago he broke his collarbone on the first stage of the Tour de France but battled through what he describes as "excrutiating pain" to finish a remarkable fourth.
"I'll be planning to stay out of trouble this time," he said.
Should he dodge the danger, Hamilton's rivals will have more than half-an-eye on him.