Alcaraz, who will surrender his world number-one ranking to Novak Djokovic at the end of this tournament, admitted he was motivated by matching Federer in defending his crown.
People on social media blasted the gestures done by a coach and the father of a 16-year-old female tennis player from Czechia, calling it inappropriate.
Former tennis star Boris Becker has been sentenced to 2 1/2 years in prison for bankruptcy fraud but a judge says he only has to serve half of that sentence.