Chris Froome is overwhelming favourite for the Tour de France but the return of former winner Alberto Contador after a one-year hiatus could trigger a classic duel to mark the 100th edition of the great cycling race.
It will also be the first Tour since American Lance Armstrong was stripped of his seven titles after admitting he cheated his way to glory from 1999-2005, leaving a huge gap in the event's records.
It is a period Briton Froome will be happy to put in the past for good.
"The fact that I'm able to finish at the front in the mountains and in the general classification means that the sport has changed since 10 years ago," said Froome, who was promoted to Team Sky leader before team mate and defending champion Bradley Wiggins withdrew from the race for health reasons.
"You learn from the past. The sport is going in the right direction and my results are proof of that."
Froome has won four of the five stage races he has entered this season.
"It definitely gives me confidence that I've had the right build-up to the Tour, that I've had the right preparation for the Tour," he explained.
"It also gives my team mates a lot of confidence, that they're riding for a worthy cause, that they know I can deliver the result.
"But having said that, once we line up on the start line in Corsica, every other race we've done early on this season folds away," added Kenya-born Froome, with a note of caution.
Froome is expected to have the upper hand in the individual time trials and will rely on a super strong Team Sky with a stunning capacity to set a high tempo in the mountains to prevent attacks - a tactic Wiggins heavily relied on in 2012.
Contador's presence, after missing last year's Tour because of a doping suspension, will definitely be felt even if the Spaniard has made little impression so far this season.
Contador, who won the Tour in 2007 and 2009, goes into the race with only one low-key victory under his belt - a stage of the Tour de San Luis in January.
Since then, the 30-year-old has been comprehensively beaten by Froome and others, despite repeated attacks in the uphill stages of the Tour of Oman or the Criterium du Dauphine.
Froome is likely to gain time in the two individual and one team time trial of this year's race, which starts on June 29, so Contador will have to make up for it in the mountains, where his rival also shines.
The race should not be decided before the last week with the 14th stage finishing up the Mont Ventoux and the 18th sending the peloton twice round the 21 hair-pins of L'Alpe d'Huez.
However, Contador is one of only five men with titles in all three grand Tours (Spain, Italy, France) while Froome has only two podium finishes - seconds in the Vuelta in 2011 and the Tour in 2012.
Contador will also be assisted by a solid team featuring Australian Michael Rogers, who was instrumental for Team Sky during last year's Tour, as well as Irishman Nicolas Roche and Czech Roman Kreuziger.
Both have relinquished their personal ambitions to help the Spaniard clinch a third title.
"There are quite a few guys whom I believe to be threats to the yellow jersey and until any of those guys lose time on the general classification they should be treated as potential yellow jersey wearers," said Froome.
"Contador is definitely not someone to write off from the group of contenders. I did come out on top in the time trial and in the mountain stages (in the Dauphine) against Contador but he cannot be ruled out."
Contador proved in winning last year's Vuelta that he never gives up, taking the overall lead in the 17th stage after launching a devastating surprise attack.
Should he and Froome falter, the indefatigable Cadel Evans, winner of the Tour in 2011, will be ready to step up, as well as fellow Australian Richie Porte, the Team Sky number two.
"Richie's results this year have been fantastic," Team Sky coach Tim Kerrison said. "He's a very very good stage racer and a strong GC contender."
The battle for the points classification green jersey is likely to be between Slovakia's Peter Sagan and Mark Cavendish, although the Briton would be happy with a brief spell in yellow.
"I would like to wear the yellow jersey after the first stage in Corsica," said Cavendish, who is 11 stages shy of Eddy Merckx's all-time Tour record of 34.
"It's the only one of the three grand tours where I haven't worn the leader's jersey, so I'd like to do that."