“Yes! Honestly, yes,” said Djokovic, when asked if he would find it strange to see the Croat as part of the Swiss legend's coaching staff. “But you know, again, we are professionals.”

It was announced in December that Ljubicic, a former world number three, would be hired in a move widely interpreted as Federer trying to find a way to defeat a dominant Djokovic, who won three Grand Slams last year and was also a finalist at the French Open.

“He (Ljubicic) knows my game, he knows the game of all Roger's opponents, and I think that's one of the reasons why Roger has hired him to be with him on the team,” said Djokovic, speaking in Doha, ahead of his first tournament of the season, the Qatar Open, which begins on Monday.

“Whether it's going to work or not, that's something to see for all of us, but I wish them all the best. He's a great guy, very calm, very composed, and I am sure Roger knows why he hired him.”

Federer has denied that the Croat has been hired just to help him overcome the Serb.

Djokovic also said he was well-rested from his winter break and was “very excited” to start again on the tour.

Given his performance last season there has been speculation that Djokovic could become the first player since Rod Laver in 1969 to win all four Grand Slams in a single season.

There is also the extra prize of a “fifth major” this season, with an Olympics gold medal up for grabs in Rio de Janeiro in August.

The Serb said he would play to win every match.

“Grand Slams and Olympic Games are the priority of the season, but it's a long season, so I can't really predict what's going to happen or guarantee if I am going to win any of the Grand Slams or all four.

“Of course, I am going to try to win every tournament and every Grand Slam that I play in, that's kind of the mindset that I have.”

Djokovic kicks off his season on Monday against Dustin Brown in the first round of the Qatar Open after the German came through the qualifiers.

Doha last year represented one of his rare failures as Ivo Karlovic beat Djokovic in three seats in the quarter-finals.

Also playing in Doha this year is Rafa Nadal and defending champion David Ferrer.

Djokovic added money was not a “priority” after it was revealed he and Federer were in a race to become the first $100 million earners in tennis.

“Money is not really why I am playing this sport,” he said.