Roger Federer and Rafael Nadal ease through to last eight in Qatar Open

TOP-ranked Roger Federer and world No 2 Rafael Nadal each won in straight sets to reach the last eight at the Qatar Open in Doha.

Nadal beat Italy's Potito Starace 6-2, 6-2, breaking him twice in each set, and will next play Steve Darcis of Belgium.

"I am happy with my form," Nadal said. "This was confirmation that I am playing well."

Federer beat Evgeny Korolev of Russia 6-2, 6-4, breaking three times in the first set and once in the second. The Swiss star, who won the Qatar Open in 2005 and 2006, will play either Andreas Seppi of Italy or Ernests Gulbis of Latvia today.

Third seed Nikolay Davydenko topped Marco Chiudinelli of Switzerland 6-3, 6-4, while Victor Troicki of Serbia beat Olivier Rochus of Belgium 6-2, 6-2.

"I am surprised to have won the match in two sets," Davydenko said. "I practised for only two weeks and then I fell sick. I was on medicine before coming here, so I am still struggling with my shots."

Elsewhere, Belgium's Justine Henin continued her successful return to the professional tour with a 6-4, 6-3 victory over Sesil Karatantcheva of Kazakhstan at the Brisbane International.

The former world No 1, playing her first official tournament in 20 months, cruised to victory in the night session to advance to the quarter-finals against Hungary's Melinda Czink. "I feel no pressure. I just want to try my best, play as many matches as possible and build my confidence," Henin said.