ATP World Tour Finals: World No 1 Novak Djokovic overcomes Kei Nishikori at O2

World No 1 Novak Djokovic remains on course for a hat-trick of ATP World Tour Finals titles in London after overcoming Kei Nishikori in the semi-finals.

The Serb, who will finish the season as the top-ranked player for the third time in four years, dropped a rare set, but still went on to complete a 6-1 3-6 6-0 success to record his 14th win in a row at the O2 Arena.

It's the last match of the season (the final) and definitely the most important one after the last couple of months so I'm looking forward to it.

He can now cap a season to remember by becoming the first man since Ivan Lendl in the 1980s to win the Tour Finals three years in a row.

The seven-time grand slam champion has been in supreme form since losing to his opponent in the semi-finals at the US Open, winning 22 of his last 24 matches, including a comfortable win over Nishikori in Paris two weeks ago.

In London, he extended his two-year-old indoor winning streak to 31 matches and heads into Sunday's final where he will play second-ranked Roger Federer.

He secured the first break in the fourth game when the Japanese trailblazer missed a backhand volley at the net and after sealing the double break in the sixth game, he served out the set in just 23 minutes.

Lack of focus

And the Wimbledon champion was left frustrated when after breaking Nishikori in the first game of the next, he double-faulted to hand Nishikori the break back, prompting some cheers from an O2 crowd eager to see a competitive contest.

Djokovic responded by sarcastically clapping the crowd and shaking his head in annoyance and the Serb admitted afterwards it had been a mistake to react as he did.

"They wanted to see a more interesting match. I made a mistake where I let my emotions go and I lost my concentration, that was totally my fault," he said.

Then in a remarkable transformation the 24-year-old world No 5 produced a brilliant effort to stun Djokovic in the eighth game and then held serve to end the Serb's remarkable record of having won his last 28 sets indoors.

Debutant Nishikori took an excellent record against top-10 rivals this year with no one having a better winning percentage in third sets (21-2), but Djokovic quickly re-established his dominance with a combination of forehand winners, strong returns and net charges while Nishikori's hopes ended following a number of unforced errors.

Nishikori could not find a way back in and Djokovic brought up his first match point with a whipping forehand winner before Nishikori double-faulted.

After his win, he told Sky Sports: "It's been a very long season and I'm sure most of the players would agree that it's been a long and exhausting year, but again, it's the last match of the season (the final) and definitely the most important one after the last couple of months so I'm looking forward to it."

Watch Roger Federer take on Kei Nishikori in the second semi-final from 6pm (GMT) on Sky Sports 3 HD.