Italian cycling legend Mario Cipollini says Alberto Contador is innocent until proven guilty and denies the sport has a serious doping problem.
Contador, who won his third Tour de France title in July, has been mired in controversy ever since it emerged he tested positive for a banned substance.
The Spaniard announced the news last month, blaming contaminated food.
"Contador has always been a champion of clean cycling and I hope he remains that way," Cipollini said.
"We want cycling to be clean and we want cyclists who ride with guts and passion up the mountains and against the clock.
"But it's a very delicate situation and I hope he clears things up: not for me but for the fans and the authorities.
"If he can do that he could emerge even cleaner than before, and it would mean the sport wouldn't lose such an enormous talent."
Cipollini's comments come after a spate of negative headlines for the sport. First came the revelation of Contador's positive test for clenbuterol, followed by news of three further failed tests by leading Spanish riders.
I'd love to see footballers submit themselves to the tests and surprise visits we agree to
The 27-year-old Contador has flatly denied any wrongdoing and has also rejected more recent allegations that his test failure was the result of an illegal blood transfusion during this year's Tour de France.
But the impression of a sport in crisis was reinforced this week when disgraced Austrian cyclist Bernhard Kohl claimed it was impossible to win the Tour de France without doping, and Italy's top anti-doping prosecutor Ettore Torri said the problem was endemic in cycling.
But Cipollini, who retired from cycling in 2008 after a glittering 19-year career, rejected these claims and said the sport had made enormous efforts to weed out the minority of cyclists who cheat.
Speaking at London's Cycle Show on Friday, the 43-year-old sprinter said: "Cycling has been in a pretty unique position for a number of years.
Contador is battling to save his reputation
"We spend a lot of time and money trying to make sure the sport is clean. I'm talking about new initiatives like biological passports, random tests, research into new substances and so on.
"I don't see other sports doing as much as cycling. I would like to see somebody compare the number of tests that cycling does with other sports.
"Let's look at football, the most popular sport. I'd love them to submit themselves to the tests and surprise visits we agree to. I'd like to see football bring in biological passports and whereabouts-style testing."
Despite the recent setbacks, Cipollini remains confident that cycling is winning the battle against drugs cheats and says he still loves the sport.
Famous for his outspoken comments and flamboyant outfits, "Super Mario" was arguably the biggest personality in the professional peloton for two decades.
But he was also a superb rider, winning a remarkable 191 races, including a record 42 stages in the Giro d'Italia, and he has lost nothing of his natural self-confidence and penchant for the sound-bite.
When asked who would win a dash to the line between him (in his prime) and current British sprint star Mark Cavendish, the Tuscan said: "Every racer thinks he will win and when you don't you always have an excuse - a team-mate didn't work hard enough or you weren't feeling great - but I'd beat Cavendish."
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