The unseeded Puerta won 6-2, 3-6, 1-6, 6-3, 6-4 in 3 hours 35 minutes and will next play the winner of the tie between Russia's Nikolay Davydenko and Tommy Robredo of Spain for a place in the final.

It was a classic claycourt encounter marked by long, punishing rallies and cat-and-mouse tactics.

The 26-year-old Puerta was the aggressor throughout, but Canas, one-year-older, soaked up all his opponent could throw at him and then pounced when he started to lag.

But Puerta from somewhere found a second wind to hit back and clinch a slot in the last four on his third match point.

In only his third tour-level event since returning from a nine-month drugs suspension, the unseeded Puerta has powered up the world rankings again.

He was in total command in the first set fixing Canas behind his baseline and using the drop shot to great effect.

Canas had saved two match points in a marathon five-setter against Frenchman Paul-Henri Mathieu in the fourth round and then went through to the last eight when Nicolas Kiefer of Germany declared forfeit before their quarter-final match.

But he was distinctly second best to Puerta at the start of the match, and was 5-0 and two breaks down before he finally managed to put up some semblance of resistence.

He broke back to 5-2, but Puerta went one set up in the next game when Canas floated a forehand long on the second set point against him.

But it all changed in the second set as Canas, one of the best defensive players on the circuit, started to nag away at Puerta's shot-making abilities and confidence.

Games went with serve until 3-3, but Canas finally broke through in the seventh game when Puerta netted a backhand drive after a energy-sapping rally. Canas then took the next two games to level the set scores.

The game was finely poised with Puerta going for the lines and Canas wall-like just behind his baseline.

But it was at this point that Canas in the quarterfinals of a Grand Slam tournament for only the second time after the 2002 French Open, imposed his authority.