Novak Djokovic
Djokovic breezed into the final with a sublime display in the second semi-final.Getty Images

Novak Djokovic remains on course to snatch the year-end world number one from Andy Murray after producing an imperious display to defeat Kei Nishikori in straight sets at the ATP World Tour Finals. The defending champion booked a winner-take-all meeting with the Briton in the final on Sunday [20 November] after breezing past Nishikori 6-1 6-1 with his most polished display for over five months.

The 12-time grand slam champion dropped just two games on his way to reaching his fifth final in a row at the season-ending tour finals as Nishikori was blown away in just 66 minutes at The O2 Arena. The routine victory follows Murray's three-hour and 38-minute win over Milos Raonic in the afternoon semi-final.

Djokovic had battled with mental demons prior to his campaign in London, however four wins in a row proves he enters the showcase final - in search of drawing level with Roger Federer and claiming a sixth title - in the sort of form which saw spend 122 weeks at the summit of the men's game. Defeat for Nishikori meanwhile means Canadian Raonic is assured of finishing the year as world number three for the first time.

After Murray and Raonic's match slipped into a fourth hour, the second semi-final threatened to be similarly engrossing. Djokovic had recaptured form close to his very best this week, while Nishikori had impressed on his way to reaching a second semi-final at the season-ending tour championships.

Both players were closely matched on paper but with nine straight victories since being ousted from the 2014 US Open by the Japan number one, Djokovic was considered the overwhelming favourite. And a quick start to the contest, only disrupted by an intruder being crushed by security staff as he attempted to get onto the court, only worked to enhance that status following a first set in which the world number two produced a near-virtuoso display.

Nishikori struck a double fault to hand Djokovic the first break, before a stunning return down the line helped claim a 4-0 lead. Following on from the longest three-set match at the ATP Finals for 25 years, the second last four clash appeared to be heading for an underwhelming climax.

A complacent Djokovic did allow Nishikori to claim one break back but that slump was only temporary as his lead was re-established straight away from the 26-year-old's next service game. Nishikori saved two set points with a pair of blistering forehands and even set up two break point chances with two stunning backhands down the line.

Two aces dug Djokovic out of bother, before Nishikori hit into the tramlines to allow the five-time champion to take the opening set in 35 minutes. Victory looked to be coming in double quick time for Djokovic when he broke Nishikori for a fourth time in the match in the first game of the second set.

The win was all-but secured when Djokovic claimed a second break as Nishikori launched a ball angrily towards the line judges - an uncharacteristic display of dissent from the Japanese right-hander. His frustration was understandable however, with Djokovic absolutely faultless as he strolled to one of his most dominating wins of the year to set-up the perfect climax to the campaign against Murray.