PARIS :Defending champion Novak Djokovic and fourth seed Andy Roddick both reached the quarter-finals of the ATP Swiss Indoors after straight sets wins.
Second seed Djokovic won 6-4, 7-6 (8/6) against Finn Jarkko Nieminen, a losing finalist in 2007, having registered seven aces and converted a single break of serve.
Roddick dealt with an unknown quantity in Kazakh Andrey Golubev, winning 6-3, 6-4.
Djokovic, who interrupted the three-year title streak of Roger Federer here in 2009, will compete for a semi-final place against Dutchman Robin Haase.
Roddick takes on David Nalbandian, whom he last faced in 2006.
Nalbandian, the 2002 champion, reached the quarter-finals of one of his favourite events by upsetting Croatian sixth seed Marin Cilic 4-6, 6-4, 6-4.
In addition to the trophy he won on his Basel debut eight years ago, the Argentine has finished runner-up at the St Jakobshalle in 2003, 2004 and 2008.
He missed his annual appointment at the indoor event last year during a medical time-out following hip surgery in May 2009.
"I feel good now. Who can say 100 percent after an operation? But I made a good recovery," said the former world number three.
"I knew that if the surgery worked, I`d be back in tennis.
"If not, well... I had no choice, the hip pain was too much." Nalbandian said he was approaching the end of what he called a "strange season".
"I couldn`t make a very clean start (in February) after my surgery," he said. "I had some muscular problems. But I played well during the American summer and started feeling better.
"I`m just trying to play these last two events of the season (Basel and the Paris Masters) well. My goal is to return to the top 10 in 2011."
Cilic was Nalbandian`s victim last August in the Washington semi-finals as he claimed a post-surgery title.
The Basel loss all but ends any chance Cilic had of qualifying for one of the three spots remaining in the eight-man field for the World Tour Finals, which start in London in just under three weeks.
Cilic broke into the ranking top 10 for the first time earlier this year but he has struggled in recent months to maintain that form and now stands 15th, having failed to win back-to-back matches since August.
Radek Stepanek will line up as the next opponent for Federer, with the Swiss home favourite and top seed hoping he can still do no wrong after two imposing victories at the hall where he got his start in the sport as a teenage ballboy.
Stepanek booked his place in the next round by beating Colombian Santiago Giraldo 3-6, 6-2, 6-0.
Serb Viktor Troicki advanced without firing a shot when Frenchman Paul-Henri Mathieu was forced to forfeit due to lower back pain.
But Richard Gasquet earned a victory as he bids for a place in the French Davis Cup finals team against Serbia next month, beating German qualifier Tobias Kamke 6-4, 7-5.