Novak Djokovic of Serbia raises the trophy after defeating Rafael Nadal of Spain in their men's final singles tennis match at the ATP World Tour Finals at the O2 Arena in London, Nov 11, 2013. [Photo/Agencies]

LONDON - The message from Novak Djokovic could not have been more emphatic as he retained his title at the ATP World Tour Finals on Monday with a crushing victory over Rafa Nadal.

Nadal deservedly ends the year as the world No 1 after an incredible comeback from injury but the way the Serb ran him ragged in a 6-3 6-4 victory at the O2 Arena was an ominous smoke signal ahead of next year.

Djokovic provided a one hour, 36 minute masterclass in power and precision and if anything the scoreline flattered Nadal, who spent most of the match dancing to his opponent's tune.

After a week of sell-out crowds at the spectacular London arena alongside the River Thames it was appropriate that the world's two best players should meet for a 39th time - the most of any modern-day rivalry.

Both players had won all their round-robin matches before cruising through Sunday's semifinals.

Rafael Nadal of Spain reacts as he holds the runners-up trophy after losing his men's final singles tennis match to Novak Djokovic of Serbia at the ATP World Tour Finals at the O2 Arena in London, Nov 11, 2013. [Photo/Agencies]

Nadal was bidding to land the title for the first time to cap a year that saw him roar back to the top of the rankings with 10 titles while Djokovic was finishing the season like a steamroller, winning 21 successive matches since losing to the Spaniard in the US Open final.

Apart from a few jaw-dropping rallies, however, the fireworks were confined to those that lit up the court as Djokovic got his hands on the trophy named in honor of the late ATP executive chairman Brad Drewett, who died this year.

"I think at the beginning he was playing much better than me, the first three games no doubt," Nadal told reporters. "After that I didn't see the difference."

The statistics offered a clue, however.

Djokovic hit 19 winners to Nadal's nine, committed less errors and served much better than his opponent, who threw in some costly double faults when he was broken early in the second set.