Serbia's Novak Djokovic looks on during his match against USA's Reilly Opelka at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

USA's Reilly Opelka plays a backhand to Serbia's Novak Djokovic during their match at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

Serbia's Novak Djokovic reacts after losing his match against USA's Reilly Opelka at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

USA's Reilly Opelka celebrates winning his match against Serbia's Novak Djokovic at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

Serbia's Novak Djokovic returns a shot to USA's Reilly Opelka during their match at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

Serbia's Novak Djokovic looks on during his match against USA's Reilly Opelka at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

USA's Reilly Opelka plays serves to Serbia's Novak Djokovic during their match at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)

Serbia's Novak Djokovic returns a shot to USA's Reilly Opelka during their match at the Brisbane International, in Brisbane, Australia, Friday, Jan. 3, 2025. (AP Photo/Pat Hoelscher)