Novak Djokovic will start his Australian Open under an injury cloud with tournament organisers nervously hoping the nine-time champion pulls through on his hotly-anticipated Melbourne Park return.
Djokovic is due to face Spaniard Roberto Carballes Baena on Tuesday night, but is entering his bid for a 10th Open triumph with a tight left hamstring that has bothered him since his Adelaide International 2 triumph.
The fourth seed is back at his favoured slam after last year's deportation saga, when he had to leave Australia for not being vaccinated against COVID-19, and is eyeing drawing level with Rafael Nadal on 22 majors.
A late withdrawal or injury-enforced retirement would be a nightmare scenario for the tournament, which has been smashed by a series of high-profile absences.
Top Australian hope Nick Kyrgios' withdrawal with a knee injury on Monday compounded the previous withdrawals of world No.1 Carlos Alcaraz and Australian women's No.1 Ajla Tomljanovic.
Two-time champion Naomi Osaka is pregnant, Ash Barty and Serena Williams have retired, while injuries also forced the withdrawals of Venus Williams, Marin Cilic and Spanish star Paula Badosa.
That didn't stop fans turning up in their droves on Monday.
The day attendance of 49,274, night crowds of 28,670 and overall attendance of 77,944 were all record numbers for the opening Monday.
Organisers will hope for a similar result on day two when Australia's Alex de Minaur kicks off his campaign as the only seeded local hope.
De Minaur will be the hot favourite in his opening match against Taiwanese qualifier Hsu Yu Hsiou, who is making his grand slam debut, while Thanasi Kokkinakis will face entertaining Italian Fabio Fognini.
The duo are among nine Australians in action on Tuesday.
Aleksandar Vukic, Kimberly Birrell, Jordan Thompson, Alexei Popyrin, Christopher O'Connell, Max Purcell and Jaimee Fourlis will also hit Melbourne Park.
Elsewhere, women's world No.2 Ons Jabeur is eyeing her breakthrough slam and will kick off her campaign before Djokovic on Rod Laver Arena against Tamara Zidansek.