Former world tennis number one Novak Djokovic has backed the introduction of VAR at the World Cup, despite seeing homeland Serbia denied a penalty in their defeat to Switzerland.
Serbia saw their lead evaporate in a fiery 2-1 defeat to Group E rivals Switzerland in Kaliningrad on Friday.
Mladen Krstajic's side were left angered when their appeals were turned down after goalscorer Aleksandar Mitrovic was dragged to the ground in a tangle with Stephan Lichtsteiner and Fabian Schar.
While disappointed with the result and VAR's failure to award a spot-kick, Serbia's 12-time grand slam champion Djokovic said he has been impressed with the technology.
"It is what it is. I wasn't in a great mood [after the result], but I thought they played well for first part of the game. After that, it was all Switzerland," said Djokovic, who faces Marin Cilic in the Fever-Tree Championships final on Sunday.
"Things could have been different if we had a penalty there. I don't know why the referee didn't decide to review it on the technology.
"Overall, I think technology has been used pretty well so far. Maybe there were situations like this, like the one [between Serbia and Switzerland], where the referee should have decided to at least see it, but it's in their hands.
"Sometimes they can't really see every situation, so I understand that they have to follow, in a way, the flow of the game and choose when to review it, choose when not.
"I thought there were some big decisions in the World Cup that were made, changed because of technology. I think that's something that was expected already more than 10 years ago in football, and I don't know why they waited for so long, but it's refreshing to see it."