Belgian Thomas de Gendt put up a superb solo effort to win the fearsome Giro d\'Italia 20th stage on Saturday, with Joaquim Rodriguez retaining the overall leader\'s pink jersey. Spain\'s Rodriguez, riding for the Katusha team, finished fourth and now holds a 31-second advantage over Canada\'s Ryder Hesjedal going into Sunday\'s 21st and final stage time trial. Despite almost doubling his advantage Rodriguez will have his work cut out to contain Hesjedal in Milan with the Garmin rider favoured by the 30km race against the clock. De Gendt\'s astonishing display of power on this stamina-sapping 219km alpine ride, culminating in the Category I climb up the Passo Stelvio, which at 2757m altitude is the highest finish of any of the Tours, also pushed him into podium contention. The 25-year-old Vacansoleil rider lept from eighth to fourth in the general standings after crossing the snow-lined finish 55sec up on Damiano Cunego. Mikel Nieve took third at 2min 50sec with Rodriguez in fourth, 3.22 down to lift him one point above Briton Mark Cavendish in the red jersey point standings. Defending Giro champion Michele Scarponi, fifth on Saturday, is placed third in the GC, 1:51s adrift. Despite losing time on Rodriguez, Hesjedal did enough in sixth to give him a great chance of creating cycling history on Sunday in Milan by becoming the Tour of Italy\'s first ever Canadian champion.