Australian rider Ben O'Connor won the Giro d'Italia's 17th stage on Wednesday in the ski resort of Madonna di Campiglio in the northern Italian Dolomites.

Portugal's Joao Almeida of Deceuninck Quick-Step maintained his hold on the overall leader's pink jersey going into Thursday's famous 'Stelvio' climb, one of the highest peaks in Europe at an altitude of 2,758km.

O'Connor, riding for the NTT Pro Cycling team, attacked on the climb 8.8km from the finish line of the 203km run through a snowy landscape from Bassano del Grappa.

The 24-year-old, who finished second on Tuesday, crossed the line alone for his first Grand Tour stage win, 31 seconds ahead of Austrian Hermann Pernsteiner, with Belgian Thomas De Gendt third a minute behind the leader.

Snow has been cleared from the road, but temperatures on the 18th stage are expected to dip as low as four degrees Celsius during the 207km run from Pinzolo to Laghi di Cancano.

The three-week race finishes in Milan on October 25.