Real Madrid's Gareth Bale is motivated by an ambition to win the Ballon d'Or and can only do so if he plays more under new coach Julen Lopetegui, according to his agent, Jonathan Barnett.

Bale, 28, said immediately after the Champions League final victory over Liverpool that he was frustrated by having lost his starting place for the biggest games under then-coach Zinedine Zidane.

The change in coaches may boost to Bale's optimism, but Barnett told Sky Sports that a player such as Bale should not need to prove his value to anyone.

"It's not about money," Barnett said. "[Bale] wants to win the Ballon d'Or and I think he can. I think he's the best [British player abroad] there has ever been ... unless someone can name me someone who's been more successful.

"I think that goal [in the Champions League final] elevated an interest in him. But we already knew how good he is. He doesn't need to prove how good he is. It was a magnificent goal and the timing was great, too."

Gareth Bale scored two goals in Real Madrid's Champions League final win against Liverpool. Getty

Barnett said he will push Madrid for assurances that Lopetegui intends to give Bale a central role in his plans for 2018-19.

"I think we have to have a chat with Real Madrid and see where we're going," Barnett said. "He wants a better year than he had last year. He wants to play more, and that's paramount to him. I think he's one of the top three or four players on Earth. For somebody like him, he has to play."

Barnett dismissed the idea that Bale, who never speaks Spanish in public, was unhappy after five seasons in Spain, saying that his thinking over his future was solely motivated by professional reasons.

"He loves his life in Spain," he said. "He has three children, and he's very happy there. But we have to see. He has to play football."