Australia's Micheal Rogers celebrates on the podium after winning the 20th stage of the Giro d'Italia, Tour of Italy cycling race, from Maniago to Monte Zoncolan, Italy. (AP Photo/Fabio Ferrari)

Monte Zoncolan, Italy - Nairo Quintana of Colombia is certain of Giro d'Italia victory barring any final stage disaster after preserving his handsome lead in Saturday's penultimate 20th stage won by Australia's Michael Rogers.

Quintana came home in a pack ahead of his closest rival Rigoberto Uran and carries a 3min 7sec lead into Sunday's closing 172km flat run.

The Movistar rider, who measures just 1.67m (5ft 6in) and finished second in last year's Tour de France, is set for his first major Tour victory as the race which began in Belfast, Northern Ireland three weeks ago, concludes in Trieste.

For Rogers this was his second win after coming home first in the 11th stage which finished at Savone.

Rogers came out on top at the summit finish, outlasting Italian Franco Pellizotti by 38secs after the two men broke away from an early escape group.

Another Italian Francesco Bongiorno, who was badly hindered by an over excited supporter, took third place, 49secs adrift of Rogers with Irishman Nicolas Roche in fourth at 1min 35secs.

Quintana and Uran crossed the line together at 4min 45secs but it had no major effect on the overall standings.

Organisers had promoted the 167km run from Maniago to Monte Zoncolan as one of the toughest in Europe with a final 10km run facing the riders with a climb of 11.9 per cent.

After a long breakaway group reached the base of the final climb with a lead of seven minutes on the peloton, Rogers and Bongiorno made their move 5km from home with the Australian making his final attack at 3km from the finish following the fan incident with the Italian.

The 34-year-old Rogers only returned to competition in April at the Liege-Bastogne-Liege following a positive doping test last season that was eventually dismissed.