Zverev, who is seeking his first Grand Slam title, admonished the crowd a bit for the reaction during his on-court interview.From NFL plays to college sports scores, all the top sports news you need to know every day.

Spectators booed as the 37-year-old Djokovic walked off toward the locker room, and he stopped, turned around and responded by giving two thumbs-up.

Twenty-four-time Grand Slam champion Novak Djokovic retired from his Australian Open semifinal match against Alexander Zverev on Friday afternoon, unable to continue due to a muscle tear in his left leg.