Andy Murray and Novak Djokovic believe that Nick Kyrgios has a lot to learn, but the top two players in the world acknowledged that he’s still gaining experience.

Coming off a title in Tokyo, Kyrgios was criticized for an apparent lack of effort in his second-round match in Shanghai. He defiantly told reporters that spectators who didn't like his performance could simply leave. He later apologized on Twitter.

Murray, who is friendly with Kyrgios, noted that players have occasionally had similar experiences, but the 21-year-old Australian has to stop exhibiting such behavior regularly.

"You know, he will be disappointed, as well,” Murray told reporters in Shanghai. “Even though he might say in here [that] he isn't, and he's not bothered, he will be. And, yeah, you just want him to learn. You know, maybe he wasn't feeling great today.

"But you have to give your best effort of what you have on that day, even if you're feeling a bit tired and lacking motivation because you have just won a tournament the week before. If he didn't do that, then he will be disappointed with himself tonight. But we're not perfect. You know, everyone makes mistakes. You just want to make sure that you learn from them and make sure it doesn't happen over and over again."

Djokovic, who has a more distant relationship with Kyrgios, also commented on the controversy.

“I haven't heard great things,” the top seed in Shanghai said. “But, yeah, we're kind of used to it when Kyrgios is a context of conversation. Not many great things are spoken about him lately."

Djokovic, though, added that he is "sorry to hear that.”

“I share the opinion of many players, and many people in the tennis world, that he's one of the greatest talents that the game has seen lately,” the world No. 1 said, “and he's got a huge potential, huge game."

The Serb also suggested that Kyrgios has time to improve.

"I mean, he's been doing well,” he said. “He's around [No.] 15 in the world, so you've got to give him credit for that. But on the other hand, he obviously has life lessons to learn. He's still relatively young.”

Kyrgios is a career-high No. 14 in the rankings.