|Venue: Melbourne Park Dates: 18-31 January|
|Coverage: Live radio and text commentary on all Andy Murray matches. Listen to Tennis Breakfast on Radio 5 live sports extra and the BBC Sport website from 07:00 GMT every day.|
Spanish third seed Garbine Muguruza became the latest leading name to make an early exit at the Australian Open as she lost to Czech Barbora Strycova.
Muguruza, last year's Wimbledon runner-up, dropped serve four times as she lost 6-3 6-2 to the world number 48.
Germany's Angelique Kerber is the only top-10 seed, at number seven, left in the bottom half of the women's draw.
Swiss Stan Wawrinka was an early winner among the men's seeds, with Andy Murray in action later on Saturday.
|Strycova in unfamiliar territory|
|The Czech, 29, had only gone beyond the third round once in 38 previous Grand Slam appearances, at Wimbledon in 2014, and is through to the fourth round in Melbourne for the first time in nine attempts.|
Seeds continue to tumble
Muguruza, 21, had looked well set to reach a second Grand Slam final as her side of the draw lost seeded players at a remarkable rate.
Second seed Simona Halep and eighth seed Venus Williams both lost in the first round and the shocks kept coming, with ninth seed Karolina Pliskova joining the exodus after defeat by Ekaterina Makarova on Saturday.
Muguruza finished with 32 unforced errors as she produced a disappointing display on her way to defeat by Strycova.
"Clearly not my best, for sure," said the Venezuelan-born Spaniard. "I think today is a very bad day, you know, at the office.
"I just couldn't find the court, my shots. Didn't really find my game."
Strycova goes through to face two-time champion and 14th seed Victoria Azarenka, who again avoided any hint of an upset by despatching Japanese 18-year-old Naomi Osaka 6-1 6-1 on Rod Laver Arena.
Kerber beat American Madison Brengle 6-1 6-3 and will next play fellow German Annika Beck.
Britain's Johanna Konta kept up her impressive form with a 6-2 6-2 win over Czech Denisa Allertova.
Unbeaten records on the line
Fourth seed and 2014 champion Stan Wawrinka will meet 13th seed Milos Raonic in round four after both men stretched their unbeaten runs to seven matches in 2016.
Switzerland's Wawrinka, champion in Chennai earlier this month, saw off Czech Lukas Rosol 6-2 6-3 7-6 (7-3), while Canadian Raonic, the winner in Brisbane, beat Serbia's Viktor Troicki 6-2 6-3 6-4.
American John Isner hit 44 aces, taking his total to a tournament-leading 101, as he beat Spain's Feliciano Lopez 6-7 (6-8) 7-6 (7-5) 6-2 6-4.
Britons battle on doubles court
Davis Cup team-mates Jamie Murray and Dom Inglot will face each other across the net in the third round of the men's doubles after both enjoyed victories on Saturday.
Murray and Brazilian partner Bruno Soares, seeded seventh, beat Poles Mariusz Fyrstenberg and Jerzy Janowicz 7-5 6-3, before Inglot and Sweden's Robert Lindstedt saw off Americans Eric Butorac and Scott Lipsky 7-6 (7-5) 6-7 (5-7) 6-4.
In the women's doubles, Fed Cup captain Judy Murray will be keeping a close eye on Court Six as Konta and Heather Watson take on Jocelyn Rae and Anna Smith.
All four players are in Murray's squad which will travel from Melbourne to Israel for the Fed Cup qualifier early next month.