Roger Federer admits it may take him time to rediscover his best form as he gets set to try to defend the Dubai Tennis Championships title.

The Swiss has not played since crashing out of the Australian Open to Andreas Seppi in the third round.

And, with world number one Novak Djokovic and Andy Murray joining Federer in headlining a strong field, the 17-time grand slam champion will need to be at his best in order to lift the trophy in Dubai for a seventh time.

Federer takes on Mikhail Youzhny, who he beat in the 2007 final, in the first round and accepts he could find it difficult at an ATP 500 event he has dominated in previous years.

"It is going to be tough as I've had a long break," Federer said. "One of the longer ones I've had in many years but it was necessary as I played a lot of tennis in the last six to eight months."

Federer has been drawn in the same half as Australian Open runner-up Murray, who will be flying solo without coach Amelie Mauresmo for the tournament as he bids to atone for his disappointing quarter-final exit at the World Tennis Tournament earlier this month.

Mauresmo is on Fed Cup duty with the France team and will not return to the Murray camp until Indian Wells in March.

"If you have a coach around it's a lot easier to do basket drills or work on specific things," Murray said. "You can get constant feedback with what you're doing."

The Brit may be disappointed not to have Mauresmo with him, but he will be expected to ease through his first-round clash with Gilles Muller as he aims to set up a potential rematch of the Australian Open final against Djokovic.

Djokovic opens his campaign against Vasek Pospisil and is confident he can achieve further success under coach Boris Becker, who has guided him to two grand-slam titles.

"We still want to achieve a lot - it's only the beginning," Djokovic said. "Especially in the second part of 2014, things really started to click together for us on and off the court.

"I learn something new from him constantly. He contributed a lot from a psychological point of view because he has been in these situations before.

"He understands the challenges I need to face, the obstacles I need to overcome to win big titles."