Roger Federer hailed Novak Djokovic's 10th Australian Open title as an "incredible" feat as the Serbian joined Rafael Nadal on 22 singles grand slams.
Although Federer became the first man to reach 20 majors when he took the 2018 Australian Open title, the Swiss great could not add to that tally before retiring last September and has been overtaken by his two greatest rivals.
With Nadal struggling to stay fit and build up form, it appears Djokovic is the most likely man to add to his haul and finish his career as the outright most successful man in grand slam history.
"Incredible effort, again! Many congratulations," Federer wrote in an Instagram story, acclaiming Djokovic's straight-sets win over Stefanos Tsitsipas in Sunday's final at Melbourne Park.
Djokovic's Professional Tennis Players Association co-founder Vasek Pospisil described the Serbian as the tennis "man of steel". Fellow ATP Tour stars Denis Shapovalov and Holger Rune also sent messages of praise on social media to Djokovic, as did Jamaican sprinting legend Usain Bolt.
