Novak Djokovic congratulates Jannik Sinner on his four-set win at the 2024 Australian Open. (Joel Carrett/AAP PHOTOS)"He's just playing on such a high level right now," Djokovic said ahead of his mind-blowing 55th grand slam semi-final and 13th in Australia. A respectful Novak Djokovic watches as Lorenzo Musetti retires from their AO quarter-final. (James Ross/AAP PHOTOS)Djokovic knows he's had a charmed run, some blessed fortune he probably needs while pursuing grand slam No.25 at almost 39 years of age. Novak Djokovic is renowned for his professional, athleticism, mobility and flexibility.