Roger Federer had an even easier ride through to the next round after Denis Istomin retired after 36 minutes of their match with the Swiss leading 5-2.

Second seed Novak Djokovic saw off the challenge of fellow Serb Viktor Troicki 6-3 7-5 to record his 100th victory at a Masters 1000 event and set up an enticing meeting with David Nalbandian, who won through after John Isner retired from their match leading 5-4.

It was not all plain sailing for the top-ranked players, however, as fourth seed Andy Murray was pushed to three sets before overcoming 58th-ranked Frenchman Jeremy Chardy 6-3 6-7 (7/3) 6-2.

Fifth seed Robin Soderling needed to come from a set down to beat former world number one Lleyton Hewitt 4-6 6-3 7-5 while Nikolay Davydenko (sixth) was also pushed all the way by Robby Ginepri 6-2 6-7 (7/5) 6-2.

Spain's Fernando Verdasco, the eighth seed, was the highest-ranked player to fall as he was beaten by wildcard Mardy Fish 7-6 (7/1) 7-6 (7/4).

Big-serving Latvian Ernests Gulbis also sprung a surprise as he fired down 21 aces to beat 13th seed Jurgen Melzer 6-7 (10/8) 6-3 7-6 (7/5) and book a third-round meeting with Murray.

Ninth seed Andy Roddick did just about enough to beat world number 50 Thiemo de Bekker 7-6 (7/4) 6-4 while David Ferrer (10) survived a tough-looking encounter with 21st-ranked Sam Querrey 7-5 6-2.

World number 32 Julien Benneteau will play Nadal in the next round after he beat Stanislas Warwinka 6-4 6-2, while Germany's Philipp Kohlschreiber earned himself a shot at Federer after recovering from a terrible second set to beat qualifier Alejandro Falla 6-0 1-6 6-3.

France's Richard Gasquet progressed with a 6-4 6-2 win over Michael Berrer.