Why Alexander Zverev was once booed by the crowd during an interview after beating Roger Federer at the ATP Finals

Alexander Zverev was booed by fans at London's O2 Arena during his post-match interview after defeating Roger Federer 7-5, 7-6 in the 2018 ATP Finals semifinal. The crowd reacted negatively after Zverev stopped play during a critical second-set tiebreak rally when a ball boy dropped a ball behind Federer, triggering a let under hindrance rules.

Zverev subsequently served an ace on the replayed point and secured the victory before expressing sadness over the crowd's reaction. In his post-match press conference, Federer acknowledged the interruption affected him and described the decision to halt the rally as bold, but confirmed replaying the point was normal once the hindrance was validated.