A ruthless Rafael Nadal extended his winning streak on clay to 68 matches on Wednesday as he opened his bid for a third successive Barcelona Open title with a 6-1 6-2 demolition of Belgian Kristof Vliegen.

The top seed needed exactly one hour to advance to the third round, giving up just one more game than he did when beating Vliegen in Monte Carlo last week.

Vliegen held serve in the opening game but that was as good as it got as a rampant Nadal reeled off six straight games.

Nadal broke serve again early in the second set and though the Belgian did manage to win two games the result was never in doubt.

The Spaniard will meet the winner of the all-Swedish clash between 13th seed Robin Soderling and former Australian Open champion Thomas Johansson.

Nadal is bidding to become only the second man, after Swede Mats Wilander, to win the Barcelona Open in three successive years.

Second seed Nikolay Davydenko overcame a troublesome right shoulder and a difficult opponent in fellow Russian Yuri Schukin to reach the third round.

Davydenko, beaten in his first match in Monte Carlo last week, struggled for form again before scrambling his way to a 6-4 3-6 6-2 victory.

The world number four looked on course for an easy win when he led by a set and 2-0, but world number 218 Schukin, who was appearing in his first ATP Tour event of the year, hit back to level.

Davydenko was then broken in the first game of the final set but after having treatment at 1-2 reeled off the next five games to set up a clash with Italian Filippo Volandri, who ousted Spanish 14th seed Nicolas Almagro 6-7 6-4 6-1.

Eighth seed Juan Ignacio Chela also advanced with a 6-3 6-3 victory over American Vince Spadea.

He will play Potito Starace, who beat Marat Safin's conqueror and fellow Italian Simone Bolelli 6-4 6-3.

Twelfth seed Guillermo Canas hammered Czech Jiri Vanek 6-1 6-1, while former Barcelona champion Carlos Moya ended the comeback of Felix Mantilla with a 3-6 6-3 6-4 victory over his fellow Spaniard.

Mantilla, in his first tournament for 18 months after overcoming skin cancer, pushed Moya for more than two hours before the former French Open champion sealed victory on his second match point.