Buenos Aires - Top-seeded Rafael Nadal overcame some uncharacteristic nerves to surge into the quarter-finals of the ATP Argentina Open on Wednesday with an efficient 6-4, 6-0 victory over Argentine qualifier Facundo Arguello.
Nadal, ranked fourth in the world, needed just 64 minutes to win his opening match in the clay court tournament, booking a clash with Federico Delbonis.
The Spaniard's 714th career win gave him sole possession of 10th on the all-time list in the Open Era, ahead of Boris Becker.
Nadal admitted he felt a few nerves opening his Buenos Aires campaign after a semi-final loss to Italian Fabio Fognini in Rio last week.
"It's never easy to open when you have lost a match like the one I lost in Rio de Janeiro," he said. "I started a little nervous, and Arguello played very well in the first set.
"In the second I felt more comfortable and I was able to attack more."
Nadal's loss to Fognini - which ended a run of 52 straight semi-final clay court wins stretching back 12 years - saw the Spaniard drop from third to fourth in the world, the first time he hasn't figured in the top three since August 2013.
This week he's trying to reassert his dominance on clay. He is one clay court title away from Guillermo Vilas' record of 46 triumphs on the surface.
Delbonis, in a re-match of last year's Sao Paulo final, once again triumphed over Italian Paolo Lorenzi with a 6-4, 6-2 win.
Third-seeded Pablo Cuevas reached his third straight quarter-final with a 7-6 (7/4), 6-1 win victory over Guido Andreozzi.
Cuevas produced seven aces to beat the local wild card. He will next face hometown favourite Juan Monaco, who upset fellow Argentine and fifth seed Leonardo Mayer 6-4, 6-4.Results on Wednesday from the ATP tournament in Buenos Aires (x denotes seeding):
Rafael Nadal (ESP x1) bt Facundo Arguello (ARG) 6-4, 6-0
Federico Delbonis (ARG) bt Paolo Lorenzi (ITA) 6-4, 6-2
Juan Monaco (ARG) bt Leonardo Mayer (ARG x5) 6-4, 6-4
Pablo Cuevas (URU x3) bt Guido Andreozzi (ARG) 7-6 (7/4), 6-1