World number one Rafael Nadal finally kickstarts his 2018 season Monday as he guns for a 17th Grand Slam title at the Australian Open, while Caroline Wozniacki spearheads the charge among the women.
The Spaniard insists he is feeling fine and ready to go deep at an event that he has only won once -- in 2009 -- among his string of major triumphs.
This is despite a chequered lead-up with a niggling knee injury preventing him playing a warm-up tournament for the first time ever ahead of the opening Grand Slam of the year.
"It's a new situation for me. But I feel good," said the 31-year-old, who first played at Melbourne Park in 2004.
"I feel that I had a good week-and-a-half of practices. I really hope to be ready."
Nadal, who faces the Dominican Republic's Victor Estrella Burgos in a night match on Rod Laver Arena, lost an epic Australian Open final last year to Roger Federer, who gets his campaign underway on Tuesday.
Fellow multiple Grand Slam winner Novak Djokovic, seeded 14, also starts on Tuesday, along with former world number one Maria Sharapova.
Tempestuous Australian Nick Kyrgios is also in action on Monday, buoyed by winning the lead-up Brisbane International in front of his home fansHe has the late match on Hisense Arena, against Brazil's Rogerio Dutra Silva.
Third seed Grigor Dimitrov and American eighth seed Jack Sock are also due on court with Melbourne's notoriously fickle weather set to dish up a cool and cloudy day with the chance of showers.
Temperatures are forecast to jump to 38 Celsius (100 Fahrenheit) later in the week.
Denmark's Wozniacki, riding high in the rankings again at world number two, starts her quest for a maiden Grand Slam title against Romanian Mihaela Buzarnescu on Margaret Court Arena.
"I think I've improved everything," she said on her resurgence.
"I'm healthy. I have the opportunity to play here. I'm just going to enjoy that, see where it takes me."
French Open champion Jelena Ostapenko is aiming for a second major title, but her form has slumped this year and she faces a tough battle with veteran Italian Francesca Schiavone first up.
Last year's finalist and fifth seed Venus Williams also has a tricky first round encounter Monday against Belinda Bencic, who is fresh from winning the Hopman Cup with Swiss teammate Federer.
Williams' sister Serena, the defending champion, has pulled out of the tournament after giving birth to her first child.
US Open champion Sloane Stephens takes on China's Zhang Shuai while American big-hitter CoCo Vandeweghe, a semi-finalist last year at Melbourne Park and Flushing Meadow, opens her account against Hungary's Timea Babos.
Top seed Simona Halep plays on Tuesday.