Li Na battles through on return to action
Li Na of China poses with the trophy following her victory over Dominika Cibulkova of Slovakia in the women's singles final on day 14 of the 2014 Australian Open tennis tournament at the bathing huts on Brighton Beach in Melbourne on January 26, 2014 - by Mal Fairclough
The top-seeded Chinese player needed two and a quarter hours to overcome blustery wind and Rybarikova, the world number 32, 6-1, 5-7, 6-2, which reversed the result of their only previous meeting in 2009.
That was when Rybarikova denied Li a grass court title at Birmingham, England, winning the final of a Wimbledon warm-up event; five years later Li is a better and more ambitious player.
"When I was training with Carlos (Rodriguez, her coach) I was working mentally, you know," she said.
"He thinks technique is not a big problem for me, but if I cannot control myself I become a big opponent for myself.
"So I have changed my training on the court a lot. But also off the court.I have changed a lot."
She took five games in little more than 20 minutes, but errors flowed more frequently from her racket in an up-and-down second set.
During that phase Rybarikova played intelligently, tenaciously, and with variety, although she looked a little jaded in the latter stages of the final set, perhaps an aftermath of Tuesday's three-hour match with Francesca Schiavone, the former French Open champion.
Li responded well to the challenge of a final set, breaking serve at once, saving a break back point in the fourth game, and maintaining only a slightly lower level of aggression but with importantly fewer errors.
It was as well she did, for this was a day in which more seeds went out - two of the better known ones - making eight out of the 16 gone half way through the third day.
Ana Ivanovic, the ninth-seeded former French Open champion from Serbia, lost 4-6, 6-1, 6-3 to Klara Zakopalova, the world number 34 from the Czech republic, while Samantha Stosur, the 12th-seeded former US Open champion from Australia, went down 6-4, 4-6, 6-1 against Jana Cepelova, the world number 82 from Slovakia.
Neither was helped by being scheduled on outside courts where the effect of the wind was often greater.
The centre court, by contrast, saw a great escape by Petra Kvitova, the third-seeded former Wimbledon champion, to win 6-2, 2-6, 7-6 (9/7) against Venus Williams, the seven times former Grand Slam champion, who was producing flashes of her formidable best in the match of the tournament so far.
Williams led 4-1 in the final set and would have reached 5-1, with a double break of serve, had she not unaccountably put a drop shot into the net with the court wide open.
Kvitova struck the ball so resolutely that she often forced her opponent to contain and defend, but missed two match points, one when she failed to close the match out on her serve at 5-4, and another at 6-5 in the tie-break.
When Williams got a match point of her own at 7-6 it looked as if she would progress but Kvitova launched an improbable forehand blast down the line and completed a memorable win two points later by forcing a forehand error from her opponent.
"I remembered the match I lost here last year," Kvitova said, referring to the 4-1 lead she let slip in the final set in a thrilling loss to Serena Williams.
"So I am really glad I came back."