Rotterdam - Tomas Berdych kept his indoor record an unblemished 8-0 this season as the Czech overpowered Italy's Andreas Seppi 6-3, 6-4 on Friday for a place in the semi-finals of the ATP Rotterdam Open on Friday.
But the second-seeded perfectionist was slightly annoyed after losing his only serve of the match in the second set, a mistake which he quickly rectified to get the contest back on level-pegging.
"I played a good match but I'm not happy with that error," said the world number seven, who was unable to play his Rotterdam quarter-final a year ago after coming down with a fever.
"I was trying to keep my level high and I did it save that one game. But I still managed to win in two sets so it's all okay at the end.
"Of course I have hopes of winning the tournament but it is one match at a time for me," said the player who won the Montpellier title this month.
Berdych will await a Saturday opponent from third seed and tournament debutant Juan Martin Del Potro, who was playing Serb seventh seed Viktor Troicki.
Berdych claimed his 67-minute victory over the 45th-ranked Seppi on a fifth ace of the afternoon at the Ahoy stadium after breaking the Italian three times.
Berdych took a 3-2 lead in their series after last playing Seppi in 2008.
The other two quarter-finals featured top seed Roger Federer playing Jarkko Nieminen after passing into the last eight through an injury withdrawal from second-round opponent Mikhail Youzhny of Russia.
World number three Federer is playing Rotterdam for the first time since he won the 2005 title.
French fifth seed Richard Gasquet was bidding for the semis against Russian veteran Nikolay Davydenko, whom he leads 3-1.