MADRID (AFP) - Defending champion Rafael Nadal continued his serene progress into the quarter-finals of the Madrid Open with a 6-2, 6-2 win over Italy's Simon Bolelli on Thursday.

Nadal has yet to win a European clay court tournament this season after defeats to Novak Djokovic at the Monte Carlo Masters and Fabio Fognini at the Barcelona Open last month.

However, he remains the heavy favourite in the Spanish capital in the absence of world number one Djokovic and will continue his quest for a fifth Madrid title against Bulgaria's Grigor Dimitrov on Friday.