Serbian tennis player Novak Djokovic (C), accompanied by his father Srdjan Djokovic (L) and his mother Dijana Djokovic, celebrates 311 weeks as world number one with his family and supporters in front of family restaurant "Novak" in Belgrade, on March 8, 2021. Novak Djokovic set a new landmark of 311 weeks as world number one on March 8, 2021, one week longer than Roger Federer whose tally of a record 20 Grand Slam titles is now firmly in the Serb's sights. "Big day today," the tennis superstar wrote on Twitter. Djokovic, 33, won his 18th major at the Australian Open in February.,Image: 596070758, License: Rights-managed, Restrictions: , Model Release: no, Credit line: Profimedia