LONDON • Novak Djokovic handed Japan's Kei Nishikori a brutal lesson in hard-court tennis as the Serb began his bid for a record fourth successive title at the ATP World Tour Finals with a 6-1, 6-1 win yesterday.

The world No. 1 was at his unrelenting best as he showed the kind of form that has made him an unbeatable force on indoor hard courts for more than three years with a 65-minute demolition job.

Djokovic subjected world No. 8 Nishikori, in his second appearance at the prestigious season-ender, to an array of heavy-duty groundstrokes, cruel lobs and flying aces as he chalked up his 38th successive win on an indoor hard court dating back to October 2012.

The Serb, who has lost only five times during a stellar season, still has to play round-robin matches against six-time champion Roger Federer and Tomas Berdych before the top two players in the group advance to next weekend's semi-finals.

But he has already reached a career-best tally of 79 wins in a single season.

"It's the best season, best year of my life," said Djokovic, who received an ATP World No. 1 trophy in a special presentation yesterday after being assured of topping the year-end rankings.

"I've been experiencing some of the peak time right now and everything got together," added the 28-year-old following his 23rd successive win.

"I've had lots of success, but 2011 and 2015 definitely stand out. I'm looking back with great pride and joy. My team definitely plays a part in this."

In both seasons, the 10-time Major champion won three out of the four Grand Slams.

REUTERS