Six weeks after completing one of the greatest seasons in tennis history, Novak Djokovic begins his 2016 campaign and warm-up for his Australian Open defence in Qatar.

The Serbian, also current holder of Wimbledon and the US Open, heads a strong field at the Qatar Open starting in Doha on Monday, which also includes Rafael Nadal, Tomas Berdych and defending champion David Ferrer.

All eyes though, at least at the start, will be on Djokovic to see if he can maintain the exceptional heights he achieved last year and to gauge his form ahead of the first Grand Slam of the year, which begins in Melbourne on January 18.

The 28-year-old dominated men's tennis last year, all but sweeping away the competition to take three majors, make 15 consecutive tour finals and win more than $21 million (19 million euros) in prize money.

He also became the third man to reach all four Grand Slam finals in a year, losing out only in the French Open to Stan Wawrinka.

Given his achievements last season, Djokovic must be looking to 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 in August.

"Here we come again to a new season," Djokovic said in an upbeat statement before arriving in Qatar on December 30.

"I'm so excited to come back and perform at my best in this season opening tournament, stay tuned!"

Last year though, Doha represented one of his rare failures.

The big serving Croatian Ivo Karlovic beat him in three seats in the quarter-finals.

The other big story in Doha is Rafael Nadal.

Now the world number five, Qatar should give some indication if the Spaniard is returning to form as he suggested he might be at the end of last season.

Nadal said he's had a great pre-season training at home in Mallorca and told journalists in the UAE at the end of last month that he aims to be "very competitive" during 2016.

He is the number two seed in Doha and could barely do worse than he did 12 months ago when he crashed out in the first round, losing to Germany's Michael Berrer in three sets.

The previous year, Nadal, 29, had won in Qatar.

- Big prize money -

This year's defending champion is Nadal's dogged compatriot David Ferrer, so he may feel himself a little unlucky to be seeded fourth.

Ferrer beat the Czech Berdych, this year's number three seed, in straight sets in January 2015, one of five tournaments he won last year as the 33-year-old showed no signs of slowing down.

"I will be there to defend my title and I hope I will be able to do so," he said in a statement released ahead of the tournament.

Also playing this year are the world number 29 Andreas Seppi and Argentina's Leonardo Meyer, ranked 35.

The Qatar Open is played outdoors on a hard court and lasts from January 4-9.

Temperatures for the week are predicted to be around the low 20s Celsius, (high 60s, low 70s Fahrenheit).

Given the riches of Qatar, it is unsurprising that total prize money for the event is $1,189,605, the largest purse for an ATP World Tour 250 event.

The draw for the first round takes place on January 2.

The tournament has been held since 1993 when a 25-year-old Boris Becker triumphed beating Goran Ivanisevic in the final in three sets.
Source: AFP