'I was surprised as I didn't expect the phone call from Novak'

Boris Becker said Novak Djokovic approached him to become his head coach the day the Serb lost the world No.1 ranking to Spaniard Rafa Nadal in October this year.

Djokovic's announcement this week that the German six-times grand slam champion was to become his coach was greeted with surprise and Becker himself said it had been unexpected.

"I was approached by Novak and his manager while he was playing in Beijing," London-based Becker told BBC Sport on Friday. "He decided he needed somebody in his corner that had been there and done it.

"I was surprised - I didn't expect the phone call. I was very honoured."

Marian Vajda, who has been 26-year-old Djokovic's coach for each of his six grand slam titles, will continue as part of the team but Becker is set to assume head coach responsibilities at the forthcoming Australian Open which starts on January 13.

It will be Becker's first foray into coaching a top-level player and he said he would put 100 percent into it.

"This isn't a half-hearted job, it wouldn't be right for him or for me," Becker said. "You're in it to win it. You either go at it fully or you don't - either I commit myself or I don't commit myself."

Becker joins another former world No.1 and multiple grand slam winner Ivan Lendl in the coaching circle after the Czech-born American teamed up with Andy Murray at the start of 2012 and has since guided the British player to two major titles.

"When Ivan was appointed, I thought about what took some of these guys so long to talk about some of these all-time greats (as coaches)," said Becker.

"There was a generation that really changed tennis and the way we played in the 1980s is not that different to how we're playing today."