While the world's best players seem pretty much unanimous in their enjoyment of the trip Down Under to start the season, the prospect of temperatures regularly exceeding 40 degrees Celsius (104 Fahrenheit) this week is a less enticing prospect.
Doubles specialist Nenad Zimonjic was blunt when asked in Sydney on Saturday what was the biggest threat to his bid for a fourth grand slam title with Daniel Nestor over the next two weeks.
"Heat," he deadpanned.
His fellow Serbian Djokovic opens his campaign for a fifth Australian Open title against Slovakia's Lukas Lacko in the first evening match on Rod Laver Arena before Williams, seeking her sixth, tackles local hope Ash Barty in her first round tie.
The evening starts means they will escape the worst of the heat, which is forecast to peak at 44 degrees Celsius (111 Fahrenheit) on Friday, and, as Djokovic pointed out, high temperatures are nothing new in Melbourne in January.
"I am expecting to play in a big heat," said Djokovic. "I remember the 2008, '9 and '10, there were several days I played in extreme heat. So I know how tough it is.
"But it's the same for myself and my opponent so you have to adjust to it."
A level playing field it might be, but energy-sapping conditions could expose anyone who arrives at the tournament in less than top notch condition or picks up an injury in an early match.
Twice Australian Open finallist and former French Open champion Li Na also opens her campaign on Monday against qualifier Ana Konjuh on Hisense Arena, while Spain's David Ferrer, seeded third in the men's draw, takes on Colombian Alejandro Gonzalez.
The relative paucity of big names on court on Monday reflects a disparity in the two halves of both draws but particularly that in the men's singles.
Second seed Djokovic, aiming for a fourth straight title, is the only member of the "Big Four" in the bottom half of the draw with top seed Rafa Nadal, Roger Federer and Andy Murray all in the top half.
Women's top seed Williams has such a superior record against all of her main rivals that she is probably more concerned about injury, which prevented her playing in Melbourne two years ago and led to a quarter-final departure last year.
Melbourne's famously changeable weather is another concern and the American was quick to recognise the irony of a Tweet she sent out earlier in the week complaining about the cold.
"I should have kept my mouth quiet and dealt with the cold weather," she said.
- Sports & Recreation
- Australian Open
- Daniel Nestor