Roger Federer and Rafael Nadal wasted little time booking their places in the last eight of the Qatar Open in Doha.

Top seed Federer needed just 63 minutes to see off the challenge of Evgeny Korolev in his second-round match, dispatching the Russian 6-2 6-4.

The Swiss broke his opponent four times in the match, winning 84 per cent of points on his first serve.

Nadal was on court for just nine minutes more than his great rival, posting a 6-2 6-2 victory over Italy's Potito Starace.

The Spanish second seed also had four breaks of serve during his match to set up a quarter-final clash with Belgian qualifier Steve Darcis, who beat Younes El Aynaoui 6-3 6-1.

Third seed Nikolay Davydenko was another convincing winner today, overcoming the challenge of Marco Chiudinelli 6-3 6-4.

Viktor Troicki, the fifth-seeded Serbian, also advanced to the last eight thanks to a 6-2 6-2 win over Olivier Rochus.

Troicki's next opponent will be Poland's Lukasz Kubot, who was a 6-2 7-6 (7/5) victor over Sergiy Stakhovsky of Ukraine.

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Seventh seed Ivo Karlovic came from a set down to beat Benjamin Becker of Germany in their second-round match.

The big-serving Croatian prevailed 4-6 6-3 6-2 to set up a meeting with Davydenko in the quarter-finals.

Ernests Gulbis of Latvia was rewarded for his 6-4 7-5 win over Italian Andreas Seppi with a last-eight contest against top seed Federer.