Record-setting Williams, Li advance at Australian Open
Serena Williams of the US celebrates after victory in her women's singles match against Slovakia's Daniela Hantuchova, on day five of the Australian Open tournament, in Melbourne, on January 17, 2014 - by Saeed Khan
The American five-time champion, making light of one of the city's worst ever heatwaves which halted play on Thursday and has caused chaos in the surrounding area, dispatched Daniela Hantuchova to advance.
Li fought back from a match point against Czech Lucie Safarova to stay on course for her second straight final, and in the men's draw third seed David Ferrer strengthened his challenge with a win over Jeremy Chardy.
Despite a fourth straight day of temperatures over 40 Celsius (104 Fahrenheit) -- a run not seen since 1908 -- Williams was untroubled in her straightforward 6-3, 6-3 win over Hantuchova.
Shielded from the sun by a pink cap, the 32-year-old world number one wielded a killer serve as she overpowered the Slovak in 80 minutes, setting up a meeting with Serbia's Ana Ivanovic or Australian Sam Stosur.
"It was hot but you have to play, you have to be ready and prepare yourself mentally. I'm excited to get through," Williams said.
It was Williams' 61st victory at the tournament, breaking the record set by 11-time champion Margaret Court up to 1975. Williams' first Australian Open win was on her debut aged 16 in 1998.
Asked which had been her favourite victories, she replied: "All the finals I was able to win."
Li soon joined Williams in the next round but she took a very different route after flirting with disaster in a three-set struggle with Safarova.
Li saved a match point in the second set then played a nerveless tiebreak before taking it 1-6, 7-6 (7/2), 6-3 in a two-and-a-half hours for her seventh straight win over the Czech.
"In the beginning she played very nice, very good and it was tough to find any rhythm," said the popular Li, who has more than 10 million fans on Chinese social media.
"I'm happy I was able to fight and win the match. I just tried to play at the baseline and move the ball around the court."
Li will now play Russia's 22nd seed Ekaterina Makarova, who beat Romania's Monica Niculescu, for a place in the quarter-finals.
Italian Flavia Pennetta beat Mona Barthel to set up a clash with Germany's world number nine Angelique Kerber, who downed American Alison Riske.
In the men's draw, Spain's super-fit Ferrer again proved impregnable as he ground down France's Chardy 6-2, 7-6 (7/5), 6-2 to reach his 15th consecutive Grand Slam fourth round.
"I am very proud of that, I like to play consistent and over the last four to five years I have been getting some good results," said last year's semi-finalist, who plays Germany's Florian Mayer next up.
Despite temperatures 42 Celsius, organisers opted not to repeat Thursday's use of emergency rules which allow them to suspend play on outside courts and close the retractable roofs on the two main stadiums.
The heatwave has caused controversy over the difficult playing conditions and has also set off hundreds of bushfires in the surrounding state, with one person dead.
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