Top seed Nadal faced a qualifier for the third straight time at this year's tournament but found India's Somdev Devvarman a much trickier challenge than his previous two matches.

Devvarman, who beat 22nd seed Marcos Baghdatis in the second round, broke Nadal in the opening service game but then couldn't stop the Spaniard from drawing level at 2-all. The Indian player stayed with Nadal but the world number one eventually closed out the set 7-5.

The second set was a little easier for Nadal and in the final game, broke Devvarman to love to record a 7-5, 6-4 victory.

In the second match of the night session, three-time champion Roger Federer overcame the challenge of American 18 year-old Ryan Harrison 7-6 (7-4), 6-3.

Federer, 29, twice dropped serve when trying to close out the first set, after some inspired play from the young American and in the final stages of the match, saved three match points on his own serve, before finally succumbing in Federer's next service game.

The former world number one was full of praise for Harrisons effort in his interview.

“I thought he played really well under the circumstances.  It's not easy coming out playing a night session against a top player, and I thought he did really well.  He competed great.  Believed in his chances.  That's exactly what he's supposed to do. But he bounced back after a tough first game, and that was impressive to see.”

Elsewhere, Argentine Juan Martin Del Potro saw off Philipp Kohlschreiber in a tough 7-6 (7-3), 7-6 (9-7) win. 22 year-old Del Potro now goes on to meet Tommy Robredo in the last eight after the Spaniard beat Sam Querrey 6-1 6-3.