Rafael Nadal's serene progress towards yet another clay-court title continued on Thursday as the world number one breezed past Guillermo Garcia-Lopez at the Barcelona Open.

The King of Clay, searching for his 11th crown at this ATP 500 event, must defend the trophy if he is to stay above Roger Federer at the rankings summit.

And, on this form, few would bet against Nadal doing exactly that as he thumped his compatriot 6-1 6-3 to cruise into a last-eight meeting with Martin Klizan, conqueror of Novak Djokovic earlier in the tournament.

Nadal's victory was his 16th in succession on the dirt, while he extended his record of consecutive sets won on this surface to 40.

Garcia-Lopez came in fresh, having benefited from Kei Nishikori's injury-enforced retirement on Wednesday, but the world number 69 - had he not been before - was soon aware of the scale of the task facing him.

Known for his power and rock-solid defence, Nadal showed a deft touch to earn the opening break of the match and a 3-1 lead in the first as a backhand slice died dramatically on his opponent and only the net was found in response.

A stunning cross-court backhand winner secured a second break in the next service game of Garcia-Lopez, who buried a forehand into the net from a looping Nadal serve out wide to hand the defending champion the lead.

Garcia-Lopez could ill-afford to offer Nadal any freebies but he did precisely that in double-faulting to give his opponent a break to begin the second, but the 10-time winner showed he was more than capable of earning the points himself with a remarkable backhand down the line hit from almost on the laps of the spectators.

Those same fans were soon cheering another Nadal break, much to Garcia-Lopez's frustration, and although he hit back with one of his own, the end result was never in doubt as the clay-court juggernaut rumbled on.