TOKYO (AP) -- Top-seeded Juan Martin del Potro advanced to the Japan Open quarterfinals with a comfortable 6-2, 6-2 win over fellow Argentine Carlos Berlocq on Wednesday.
Del Potro broke Berlocq's serve twice in the second set and closed out the match in 1 hour, 6 minutes. After Tuesday's three-set victory over Marcos Baghdatis, del Potro said it was good to find his rhythm.
''I played a lot better than yesterday,'' del Potro said. ''I served well, my forehand was strong and I was able to break his serve and be aggressive. I had control of the match all the time which was important to me.''
Del Potro was a late addition to the tournament after Andy Murray, the 2011 champion, withdrew due to a back injury. Del Potro is seeking his third title of the season following victories in Rotterdam and Washington.
In the day's only upset, Ivan Dodig of Croatia ousted second-seeded Jo-Wilfried Tsonga of France 6-4, 7-6 (5).
In other matches, third-seeded Milos Raonic of Canada advanced to the second round with a 6-4, 7-6 (0) win over Go Soeda of Japan in the opening match on Center Court.
Raonic, coming off a win at the Thailand Open on Sunday, dominated Soeda with his serve, hitting 24 aces against the Japanese wildcard.
''I served really well,'' Raonic said. ''It was a bit earlier in the day than what I'm used to but I played well on the important points and did what I needed to do.''
Raonic lost in the final of last year's tournament to local favorite Kei Nishikori, who will face Spain's Feliciano Lopez in the second round on Thursday.
The fourth-seeded Nishikori is on the verge of becoming the first Japanese player to break into the top 10 and is bidding to win his second title of the season.