Boris Becker uncertain whether he will be Novak Djokovic's coach next year

Boris Becker has said he doesn't know whether he will be Novak Djokovic's coach next year, but warned that Andy Murray will have a tough time staying No. 1.

Djokovic made a change to his coaching team at the back end of the 2016 season, with Spanish spiritual guru Pepe Imaz in tow for the Paris Masters and World Tour Finals in London.

But Becker did not give an answer when asked if the addition of Imaz had created any tension in the camp, which also includes Slovakian Marian Vajda.

"I'm too much on the inside," he told The Times. "I won't comment on team members."

Speaking in a series of interviews with British newspapers at London's Royal Albert Hall, where the ATP Champions Tour's season finale is taking place, Becker, 49, also responded to questions about his future on Djokovic's team.

"We are in the process, but I can't tell you anything more than that," the six-time major winner told the Daily Mail. "I couldn't tell you yes and I couldn't tell you no."

Djokovic has won six Grand Slams since appointing Becker in Dec. 2013, and held all four major titles at the same when he defeated Murray in the French Open final in June.

"I truly enjoyed the last three years; I had a blast," added Becker. "I was in my element and I will continue to be in my element in the future. No regrets, it was an unbelievable ride."

Becker reiterated his opinion that Djokovic's motivation dipped after finally completing the career Grand Slam at Roland Garros, but also alluded to "other issues" behind the Serb's dip in form -- which he also refused to expand on.

"Look, I'm on the inside, I know everything, and I can't tell you," Becker told the Daily Mail. "I love my player and will protect him and will never say anything about that, so I will have to plead the fifth amendment."

Djokovic's form deserted him in the second half of 2016 -- he went out in the third round at Wimbledon, lost his opening match at the Olympics and was beaten in the US Open final.

Murray managed to claw back a deficit of more than 8,000 points to overhaul the Serb at the top of the world rankings, ending his season with a career-best 24-match win streak and five consecutive titles.

The last of those wins came against Djokovic in the World Tour final. With the year-end No. 1 ranking on the line, the Scot swept aside Djokovic in straight sets.

However, Becker believes Djokovic will be refocused for the new season and will start to put pressure on Murray in the battle for No. 1 when the tour moves to the clay courts.

"I still think he [Murray] is going to be riding the wave coming to Australia, and in the American events in March, because that was the only time he played badly this year," said the German.

"I think he is going to start to feel it in May. It's one thing playing up with nothing to lose but it's a whole new ballgame when you've got something to lose, the consequences of being world No. 1. There are responsibilities and expectations, so it becomes more strenuous. But I think he will be fine until the clay court swing."