Millman on the whistles for Djokovic: "Have respect for him".

The first semi-final of the Australian Open was supposed to be a battle, but in the end it was not.

After a hard-fought first set between Alexander Zverev and Novak Djokovic, the Serb, who had just lost in the tie-break, was forced to retire with a leg injury.

As he left the court, Novak Djokovic was applauded by the majority of the crowd, but a few whistles also came from the Rod Laver Arena stands.

Former professional tennis player John Millman, a consultant for Australian television, spoke about this highlight of the first Australian Open semi-final.

"It was a bit of a mess in the stadium, with some people clearly out of line. During this Australian Open, some people's behavior was inappropriate, but this one took the cake.

Novak Djokovic is a player who has won this tournament ten times. Show him some respect. He's one of the greatest players of all time, if not the greatest.

In any case, he's undoubtedly the greatest player ever to set foot on Rod Laver Arena. As far as I'm concerned, it doesn't matter how much money you spent to see him play. Have some respect for him," he concluded.