Horner thought Ricciardo was "winding him up"

Red Bull boss Christian Horner has opened up about Daniel Ricciardo's shock decision to move to Renault at the start of next season.

Christian Horner has revealed that he thought Daniel Ricciardo was "winding him up" when he told him about his decision to move to Renault in time for next season.

"I thought he was winding me up, to be honest with you," Horner told Formula One's official website, referring to the phone call he received with Ricciardo announcing his decision.

"He rang me to say I'm going to Renault. I said 'You what? Is this a wind up for the summer holidays?' But it then became very clear that was his choice and you have to respect that. Renault are a growing team, they're committing resource there.

"I think Daniel decided after a long flight to America, he decided he wanted a chance. You look at the rational reasons for that, it's difficult to understand, but Daniel obviously had his reasons.

"I think it comes back to wanting to take on, in his words, a new challenge but I also feel he sees Max (Verstappen) growing and growing in terms of speed and strength and he doesn't want to play a support tole I guess, for want of a better word, not that they are treated in any way differently.

"They would have equal status, as they always had. I could understand if it was to Ferrari or Mercedes, but it's an enormous risk at this stage of his career."