Canada's Milos Raonic advances at Japan Open
Serbian Viktor Troicki retires with injury
Tomas Berdych, Janko Tipsarevic and Milos Raonic progressed to the quarterfinals of the Japan Open with comfortable victories on Thursday.
Second-seeded Berdych of the Czech Republic had a 6-3, 7-5 victory over Alejandro Falla of Colombia, Serbia's Tipsarevic beat Marco Chiudinelli of Switzerland 6-4, 6-2 while Canadian Raonic went through when Serb Victor Troicki retired with injury when trailing 3-0 in the first set.
Tipsarevic will take on Raonic in the quarters while Berdych will play either Spain's Tommy Robredo or local Japanese hope Kei Nishikori.
Top seed Andy Murray had already booked his spot in the quarters on Friday, when he will meet Switzerland's Stanislas Wawrinka.
Berdych exhibited solid ground strokes and a strong serve throught the match at Ariake Colosseum, and closed it out with his ninth ace of the contest.
"The big difference between today and my first-round match is that I am feeling much better physically," said Berdych. "I served well and played solidly, and was able to finish it in two sets."
The first set was on serve until the sixth game, when Berdych reeled off three superb backhand winners to break and go up 4-2. Berdych took the set 6-3 in 30 minutes.
Berdych, ranked sixth in the world, won 93 per cent of his first serves in the opening set. The Czech is seeking his second title of the year after winning indoors in Montpellier, France, in February.
The 27-year-old Berdych unleashed some fierce forehands in the second set as he notched his 50th ATP Tour win of the season.
Berdych lost to top seed Murray, the defending champion here, in the semifinals at the U.S. Open last month.
In later second-round action Thursday, Juan Monaco, the fourth seed, will play Marcos Baghdatis of Cyprus, while Nishikori takes on Robredo.