Rafael Nadal’s knees were given a stern test as he was pushed all the way by Argentina’s Carlos Berlocq before booking his place in the semi-finals of the Brasil Open.
The Spaniard, in his second tournament back after a lengthy period out through injury, eventually prevailed 3-6 6-4 6-4 on the Sao Paulo clay in two hours and 24 minutes.
It was a gritty performance from world number 78 Berlocq, who saved nine of the 13 break points he faced, but it was not enough against the class of Nadal.
The number one seed will next face another Argentinian, the unheralded Martin Alund, whose impressive run continued with a straight-sets win over Italy’s Filippo Volandri.
The world number 111 had not won an ATP Tour-level match until this week but booked his place in the last four by beating Volandri 7-5 7-6 (7/5).
In the other half of the draw there was a shock as second seed Nicolas Almagro of Spain was beaten by another Argentinian, David Nalbandian.
The former Wimbledon finalist, now ranked 93rd in the world, won 7-6 (7/5) 3-6 7-6 (7/3) in two hours and 18 minutes, leaving Nadal as the only seed left in the draw.
Nalbandian, who was Nadal’s doubles partner here until the Spaniard pulled out after one match to preserve his knee, will face Italy’s Simone Bolelli, who beat Albert Montanes of Spain 6-4 6-4.