Top seeds Ash Barty and Naomi Osaka cruised into the last 16 of the China Open with straight sets victories in their second round matches in Beijing Tuesday.

World number one Barty, who received a bye into the second round, started her campaign with a 6-4 6-2 win over Kazakhstan's Yulia Putintseva, wrapping up the contest in 75 minutes. Barty fired seven aces, converted four of nine break points and smashed 23 winners in a clinical display which she said was enough to get the job done. "It was solid today without being fantastic," Barty said. "It was what we needed to do today. There were times where it was pretty good and there were times where it was challenging.

"It's a court that I think is tough to neutralize and play defence over a long period. It's definitely a court that you get your bang for buck and you get value when you try to take the initiative." Japan's Osaka, seeded fourth, needed only 59 minutes to brush aside German qualifier Andrea Petkovic with a dominant 6-2 6-0 win.

Osaka converted five break points and fired 21 winners in a one-sided contest to set up a clash with American Alison Riske, who beat Australian Ajla Tomljanovic 6-3 3-6 6-4 in the only three-set match of the day. Angelique Kerber's poor form dragged on after another early exit at the hands of Slovenia's Polona Hercog who won 6-4 6-2. Apart from a semi-final run in Osaka, 10th seed Kerber has not moved past the second round of tournaments in Zhengzhou, Wuhan and now Beijing.