Top-seeded Juan Martin del Potro moved into 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.
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.