The 2005 ProTour was the first year of the newly introduced UCI ProTour system, in which the ProTour teams are guaranteed, and obliged to, participate in the series of ProTour races. In certain ways the ProTour replaced the UCI Road World Cup series of one-day races, which in 2004 was won by one-day specialist Paolo Bettini for the third time in a row. The beginning of the ProTour saw difficult negotiations with the organizers of the Grand Tours, the Tour de France, the Giro d'Italia and the Vuelta a España. Spring classics Following tradition, had a strong showing in the early season, with a commanding control of the season opener Paris–Nice, placing American Bobby Julich on the top step of the General classification, combining his strong prologue individual time trial performance and good placing in the Mont Faron queen stage. Sprinter Alessandro Petacchi shed some weight over the winter and built up a strong base to win the classic Milan–San Remo convincingly, leading to speculation that he will be the undisputed Italian team leader for the World Cycling Championship in Madrid later in the season. Belgian sprinter Tom Boonen of showed that he was the strongest kasseinfretter, or cobble-eater, by winning both the Tour of Flanders and Paris–Roubaix cobbled classics, propelling him to the top of the UCI ProTour rankings and thus earning him the white leaders jersey. As the spring classics campaign continues, Bettini was plagued with injuries, but fellow one-day specialist Danilo Di Luca of found his best form in years and won the Tour of the Basque Country race. With his confidence boosted, he topped his form with wins in both La Flèche Wallonne and the Amstel Gold Race, leading many to speculate that he would also win the Liège–Bastogne–Liège. However, Jens Voigt committed himself to long breakaways in both la Flèche and Liège, and in the later race was joined by Kazakh Alexander Vinokourov. Together they managed to keep the peloton behind, and Voigt was beaten in the final sprint by Vinokourov. Grand tours Having earned the ProTour white leader's jersey, Di Luca further increased his lead with a stage win and fourth place in the general classification of the 2005 Giro d'Italia, joining Gilberto Simoni of in igniting the queen mountain stage of Sestriere. The same race also saw Damiano Cunego, who finished at the top UCI ranking last year, fall ill. In the end,