Novak Djokovic and Maria Sharapova were involved in a live Instagram chat, where Sharapova recalled when she got into a tangle and had to buy Djokovic dinner.
Maria Sharapova announced her retirement through an article in Vogue magazine.
Maria Sharapova lost in straight sets to Croatia's 19th-seeded Donna Vekic in the first round of Australian Open.
Wild bushfires raging across Australia have also hit tennis as players were suffering from smoke inhalation during the Australian Open qualifying event.
Maria Sharapova will line up at Melbourne Park once again after it was announced on the tournament website that she would be a wildcard.
Maria Sharapova has not played since a first-round loss to career-long rival Serena Williams at the US Open in August.
Maria Sharapova dropped out of the Austrian tournament last week but says that she could play in the Luxembourg tournament which starts October 14, even though her main focus is to get healthy for the 2020 season.
Serena Williams needed only 59 minutes to rout her Russian rival, improving to 20-2 all-time against Sharapova with her 19th consecutive victory in the rivalry.
Serena Williams is looking to match the all-time record of 24 Grand Slam singles titles won by Margaret Court when the year's final major championship gets under way Monday.
Maria Sharapova had earlier pulled out of the French Open 2019 with a shoulder injury