World No 1 Halep saves three match points to beat Lauren Davis in three sets at Melbourne
Australian Open Day 6: Kerber crushes Sharapova after Halep shows her mettle
Angelique Kerber crushed Maria Sharapova in straight sets in a battle of former champions at the Australian Open on Saturday.
The 2016 winner from Germany and 21st seed roared past the Russian 2008 champion 6-1, 6-3 in 64 minutes on Rod Laver Arena to reach the last 16.
Kerber will face either 26th seed Agnieszka Radwanska of Poland or Taiwan's Hsieh Su-wei for a place in the quarter-finals.
"I was just trying to enjoy every point," Kerber said after snuffing out Sharapova's hopes in only her second grand slam tournament back since serving a 15-month doping ban.
The hugely anticipated match up of the only two Australian Open winners - and indeed grand slam champions - left in the women's draw got top billing Saturday night on Rod Laver Arena.
"I have so many good memories on this court," said Kerber, who won her first grand slam title there two years ago when she beat Serena Williams in the final. "I knew before the match it would be a tough one."
Fighting Halep outlasts courageous Davis
Top seed Simona Halep saved three match points as she won a marathon third round encounter 4-6, 6-4, 15-13 against Lauren Davis Saturday.
American Davis lost a toenail in a third set lasting more than two hours and Halep served for the match four times before finally getting across the line on her very first match point.
"I never played a third set so long. I'm almost dead," the Romanian said.
Halep nows plays Japan's Naomi Osaka in the last 16 after almost four hours of incredible action - the longest match of the women's tournament so far.
It eclipsed the 3hr 1min that fellow Romanian Irina-Camelia Begu took to defeat Ekaterina Makarova of Russia 3-6, 6-4, 8-6 in the first round on Monday.
Pliskova prevails to reach last 16
Karolina Pliskova outmuscled fellow Czech Lucie Safarova to make the fourth round on Saturday in a testing two-set encounter.
The tattooed sixth seed, looking to win her first major, came through the tight match on Margaret Court Arena against her 29th seeded compatriot 7-6, 7-5 in 1hr 37mins.
"It was a tough match, it always is against Lucie," said Pliskova, who made the quarter-finals last year. "I'm happy I held my serve in the last game, It's a good sign because my serve is the most important key for me."
She will next play either American Bernarda Pera or another Czech Barbora Strycova who clash later.
Matches to watch on Day 6: Maria Sharapova faces Angelique Kerber hurdle
Roger Federer defends Aus Open organisers: 'You've got to play in all conditions'
Another smooth win for Keys
US Open finalist Madison Keys continued her serene progress through the draw with a 6-3, 6-4 win over unseeded Ana Bogdan on Saturday.
The 17th seed, who made the semis at Melbourne Park in 2015, has not dropped a set and breezed past the plucky Romanian, ranked 104, in 73 minutes in their third-round match on Margaret Court Arena.
"I'm really excited. I definitely feel I'm playing well," said Keys, who was one of only three Americans to make the round of 32.
She had only dropped seven games going into this match, taking just 41 minutes to get past Russia's Ekaterina Alexandrova 6-0, 6-1 in the second round and must now be rated one of the favourites going into the second week.
"Ana played great today and made me play my best tennis," Keys added.
Garcia's three-set victory
Eighth seed Caroline Garcia battled into the last 16 on Saturday to set up clash with the dangerous Madison Keys for a place in the quarters-finals.
The Frenchwoman, who won two WTA titles last year to send her rocketing up the rankings, proved too much for unseeded Aliaksandra Sasnovich of Belarus, winning 6-3, 5-7, 6-2 on Hisense Arena.
She will now play American 17th seed Keys who continued her steady progress through the draw with a 6-3, 6-4 win over unseeded Ana Bogdan.
"Madison has been going great and it is going to be big hitting from both sides," Garcia said of her next opponent.
"I haven't done too well against her before and I want to improve."
Osaka ousts Australian hope
Unseeded Naomi Osaka downed local Australian Open hope Ashleigh Barty with a comprehensive 6-4, 6-2 win Saturday to reach the last 16 of a Grand Slam for the first time.
Ranked 72, her reward is a clash with top seed Simona Halep for a place in the quarter-finals.
The powerful Japanese 20-year-old took the first set against the 18th seed in 38 minutes before racing to a 4-0 lead in the second on the back of an impressive serve.
Barty finally got on the board in her third service game but it was too little too late to the dismay of the raucous band of "Ash's Army" supporters on Margaret Court Arena.