World number three Wang Xin failed to clear the second round when she bowed to unheralded Tai Tzu-ying of Taiwan at the Japan Open on Thursday, but there was no such trouble for India's Saina Nehwal.
Saina needed some time before getting into her rhythm to score a 21-17, 21-16 victory over the Vietnam Open champion Fu Mingtian of Singapore.
"I started a bit slowly. She is very good and I didn't know how she plays. I started a bit nervous, but after that I played very well," said Nehwal, who claimed five titles last season and is a pin-up at home.
Saina, who has won only one title so far this season, at the Swiss Open in March, said the difference from last season was her ankle injury.
"I had an ankle injury for the first few months, but I'm happy that I won one title and played two finals. Again in the Indonesian Open, I played finals this year," said the 21-year-old.
"Performance-wise now my ankle is better. I'm getting back my form and I hope next season is much better."
Asked about her goals leading up to the London Olympics next year, the fourth seed said: "I want to come up in the rankings and I want to win many tournaments, beating Chinese players consistently.
"Everybody wants to win a medal (in the Olympics). I hope I win a medal, but it's not easy. Everyone is playing well. I want to give my best."
In the quarter-finals on Friday she will play the winner between Gu Juan of Singapore and Sayaka Sato of hosts Japan.
Xin, who was rated the best player in the world at the start of the year, lost to her compatriot Jiang Yanjiao in last year's final in Tokyo.
And there was more heartbreak as she ran out of steam in a close final game to go down 13-21, 21-16, 20-22.
"I couldn't do anything today. I couldn't hit the shuttle as well as I usually do," said the 25-year-old third-seeded Wang, who quickly left the court in disappointment.
Meanwhile, Tine Baun of Denmark, the 2007 Japan Open champion and fifth seed, defeated Maria Febe Kusumastuti of Indonesia 21-18, 13-21, 21-10.
In the men's singles field, the 2010 All England surprise runner-up Kenichi Tago of Japan became the first quarter-finalist when he defeated Chou Tien-chen of Taiwan 21-17, 21-11.