Business & Finance Club - Tokyo : Andy Roddick repelled dangerous Frenchman Jeremy Chardy 6-4 7-6 to reach the quarter-finals of the Japan Open on Thursday.

The American took the first set relatively comfortably but had to save a set point in the second with a tough high backhand volley before closing out the match on a tiebreak.

"He's dangerous because he plays a pretty high-risk game," second seed Roddick told reporters. "But I played the big points very well. When you're playing average that's encouraging."

Roddick, who made the semi-finals in Tokyo on his only previous appearance in 2008, is playing his first tournament since crashing out of the U.S. Open in the second round.

The world number 10 was out-aced six to five by Chardy but powered through the tiebreak 7-4 to win in a shade over an hour and a half.

"I'm at a point now where I'm not afraid to play long points any more," said Roddick, who plays French fifth seed Gael Monfils in the last eight.

"I haven't played much and I've struggled a little but it's nice not having to fight that mental battle."

Dressed in a sleeveless shirt and baggy knee-length shorts, the dread-locked Monfils looked more beach-goer than tennis player.

However, the beanpole Frenchman was all business as he wrapped up a 6-4 6-4 victory over Italy's Andreas Seppi.

Serbia's Viktor Troicki bundled out fourth seed Juergen Melzer 7-6 3-6 7-6 of Austria to set up a quarter-final with last week's surprise Bangkok winner Guillermo Garcia-Lopez of Spain.

World number one Rafa Nadal was playing Canadian qualifier Milos Raonic in Thursday's last match on center court.