The 28-year-old Li is riding a wave of confidence after shocking favourite Kim Clijsters in this month’s Sydney International final, and following her run to last year’s Australian Open semis.
“I won last week so maybe I feel more confident. I just hope I’ll continue to take this confidence and see how far away I can go,” she said.
Li, who beat Sophie Arvidsson of Sweden in straight sets in the first round before accounting for Rodina on Wednesday, added she still had room to improve.
“I didn’t feel special tonight,” she said. “This girl, I didn’t know anything about her before. I didn’t see her practice, I didn’t practice with her.
“I was thinking that many balls I hit were winners, but she still came back and hit them deep and she ran me around a lot today.”
Li now plays Czech Barbora Zahlavova Strycova ahead of a possible fourth round clash against Belarusian eighth seed Victoria Azarenka.
She could then meet Venus Williams in the quarterfinals in a rematch of 2010, when Li shocked the American to reach the final four.
“I only look one round ahead because before, I always looked at the draw and thought ‘Oh, I can be in the quarter-final or something’, and I always lost in the first round, second round,” she said.
“After that I just said, ‘Okay focus, don’t think about it too much’.”
Nishikori, who has been supported by a vocal contingent of Japanese fans, set up a clash with Spanish heavyweight Fernando Verdasco after winning 6-4, 6-3, 0-6, 6-3 against Mayer, ranked 46 places higher at 36.
The 21-year-old beat world number 15 Marin Cilic this month in Chennai and recovered strongly from a stomach upset to knock out Italian Fabio Fognini in his opening match here.
“I started well this year from Chennai. I played well there, and I’m getting real confidence here,” said Nishikori, who is mentored by high-profile coach Brad Gilbert.
“I played another good match today and beating these kind of players gives me more confidence to go on. My goal for now is to get top-50 as soon as I can.”
Last year Li and compatriot Zheng Jie, now injured, both reached the Australian Open semis in China’s best-ever Grand Slam performance.
Li also reached the Wimbledon quarter-finals for the second time in her career, before being ousted by Serena Williams. In 2009 she made it to the US Open quarters where she was beaten by Clijsters.
Indian starlet Sania Mirza is already out but declared herself back to her best after stretching former number one Justine Henin in the opening round.