Li Na sweeps into the quarters as Nishikori falls

Li, who became Asia's first Grand Slam champion at the 2011 French Open, showed her pedigree as she took apart Germany's 18th seed Julia Goerges 7-6 (8/6), 6-1 to reach the last eight for the third time.

But there was heartbreak for Nishikori, the Japanese number one, who failed to match last year's run to the quarter-finals as he went down in straight sets to dogged Spaniard Ferrer.

Li has an enduring love affair with the Australian Open after reaching the semi-finals in 2010 and finishing runner-up to Kim Clijsters a year later. Last year, she crashed out in the fourth round against the Belgian.

However, after saving a first-set set point in a tense tie-break against Goerges, the world number six was untouchable and she completed her surge into the second week in just 86 minutes.

"If I had lost the first set it could have been another story," beamed Li. "I just kept going point by point, not thinking too much."

Meanwhile Nishikori, troubled by a knee injury, was outclassed 6-2, 6-1, 6-4 by super-consistent Ferrer, the world number five, who reached the quarter-finals for the third year in a row.

For Nishikori, it was a disappointing outing after last year's run to the last eight, which went down as the best ever performance by a Japanese man.

"I tried to go aggressive, but I think I forced it too much," he said. "So I was missing too many (shots), making too many unforced errors. And also he was playing well. He didn't miss much, and he gets every ball.

"Yeah, it was tough for me to play."

It was a difficult defeat to swallow after Nishikori, the world number 18, came into the match with a winning record against Ferrer including victories at the 2008 US Open and last year's Olympics, held at Wimbledon.

Nishikori said he was "a little bit" bothered by the left knee injury which forced him out of this month's Brisbane International and which needed treatment on court.

But the 23-year-old said he was getting close to improving his record against top-10 opposition, against whom he has now lost seven of his last nine matches, and make another deep run at a Grand Slam.

"It's getting close, but, you know, there's a little more work to do. Hopefully I can beat them in a Grand Slam some time," Nishikori said.

He added: "That's my next goal, to get to a quarter-final, semi-final in a Grand Slam. The French Open is always tough for me to play, on clay courts.

"But, yeah, for sure I have a chance if I play my best tennis."

Nishikori's defeat leaves Li as the last Asian player in the competition after Japan's Ayumi Morita and Kimiko Date-Krumm, 42, both went out on Saturday.

th/mp