Novak Djokovic's US Open defeat sparks questions over legend's future

Novak Djokovic experienced his earliest US Open exit in 18 years, falling to Alexei Popyrin in the third round. The defeat adds to Djokovic's challenging year, seeing him end without a Grand Slam title for the first time since 2017. Popyrin's victory raises questions about Djokovic's future in the sport.