The 2017 season does not officially start until this weekend, but the leading players are already flexing their muscles. Roger Federer, who is returning to competition after taking a six-month break because of a knee injury, drew a crowd of more than 6,000 just to watch his first practice session here at the Perth Arena ahead of next week’s Hopman Cup, while Andy Murray and Rafael Nadal are among those playing in a three-day exhibition event that started Thursday in Abu Dhabi.

It was only 39 days ago that Murray secured the year-end world No 1 ranking for the first time by beating Novak Djokovic to win the Barclays ATP World Tour Finals in London, but the tennis schedule is unforgiving.

The Scot was back on court in Miami earlier this month preparing for the new season and flew this week to the Middle East, where he will head from Abu Dhabi to Doha for next week’s Qatar Open, which will be his only competitive appearance before the Australian Open starts in Melbourne in just 18 days’ time.

Djokovic will also begin his season in Doha, which is where he usually hones his game in readiness for the Australian Open, which he has won six times in the last nine years.

If regaining the world No 1 position from Murray is high on Djokovic’s list of priorities, he will need to find his form quickly. The Serb, who parted company with his head coach Boris Becker earlier this month, won the titles in both Doha and Melbourne at the start of this year, which means that he will have to make a successful defence of both just to maintain his current rankings points total.

Murray, meanwhile, can only improve his ranking points tally next week, having begun his 2016 campaign at the Hopman Cup, where no ranking points are on offer. The Australian Open, where Murray was runner-up this year for the fifth time, will be the only tournament in the first three months of the season where he has significant ranking points to defend, whereas Djokovic will also be defending titles at Indian Wells and Miami.

Federer returns to action for the start of the 2017 season (Getty)

A key question for Murray will be how he recovers from his exertions in the latter half of the 2016 season. The Scot reached the final of 12 of the 13 tournaments he entered between May and the end of the season, winning nine of them. He won 78 matches in the year, which was 13 more than any other player, and ended the season with 24 successive victories.

“It took me basically the whole year, right down to the last tournament, the last match of the year, to finish No 1, so that was really, really hard and it took a lot out of me physically and mentally,” Murray admitted this week in Abu Dhabi. “I was really, really tired, more tired than I’ve been at the end of any season that I’d finished before.”

While Murray and Djokovic will be fighting over the world No 1 ranking, the two other members of the “Big Four” will be hoping to have revived their careers after taking breaks to recover their fitness. Federer has not played since Wimbledon because of a knee problem, while Nadal brought his 2016 campaign to an early end in October after a succession of injury issues.

Andy Murray has a fight on his hands to maintain his No 1 status (Getty)

Federer, who resumed full training last month and has been pleased with the way his left knee has stood up to his increasing workload, will be playing in the Hopman Cup mixed team event, alongside Belinda Bencic, for the first time for 15 years. The Swiss team’s first opponents will be Britain’s Dan Evans - who was beaten by Federer at Wimbledon in the summer - and Heather Watson. Under the tournament’s round-robin format each team plays three matches, each of which comprises one men’s singles, one women’s singles and one mixed doubles.

Nadal, who added his fellow Majorcan Carlos Moya to his coaching staff earlier this month, will be opening his campaign in next week’s Brisbane International. Nadal, who in the past preferred to start his season in Doha, and the 2014 Australian Open champion, Stan Wawrinka, who was a regular in Chennai, will be playing in Brisbane for the first time. They will be joined by Milos Raonic and Kei Nishikori.

Nadal has not won a Grand Slam title for two and a half years, which has prompted growing speculation that he might retire soon, but the 30-year-old Spaniard insisted this week that he will continue playing for a good while yet.

Serena Williams has not played since being knocked out of the US Open (Getty)

Brisbane is the only Premier event of the first week of the Women’s Tennis Association season and has consequently drawn a strong field, including five of the eight players who contested the end-of-year WTA Finals in Singapore. Angelique Kerber, the world No 1 and Australian Open champion, heads a line-up that also features Garbine Muguruza, Karolina Pliskova, Dominika Cibulkova, Svetlana Kuznetsova and Carla Suarez Navarro.

Britain’s Johanna Konta, who broke into the world’s top 10 for the first time at the end of the 2016 season, will start her campaign at the Shenzhen Open in China, where her rivals will include Agnieszka Radwanska and Simona Halep. Konta will need to hit the ground running under her new coach, Wim Fissette, if she is to avoid dropping down the rankings, having reached the semi-finals of last year’s Australian Open.