Novak Djokovic vs. Roger Federer: Score, Reaction for 2015 ATP World Tour Finals

Novak Djokovic claimed his record fourth consecutive ATP World Tour title as he beat Roger Federer in straight sets at the 2015 ATP World Tour Finals on Sunday.

The Serbian triumphed 6-3, 6-4 in a comfortable win in which he simply did just enough to win over a somewhat subpar Federer.

According to BBC Sport's Mike Henson, Djokovic expressed his delight at the win and admitted to looking forward to a break in the off-season.

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I am enjoying every moment on the court, I cherish every moment after dreaming of it as a kid. Thank you everyone for making this year so special.

I am looking forward to our two weeks of holiday with my wife and son and away from tennis for a bit. Congratulations to Roger, it was another epic match today and I hope you enjoy your time off with your family.

"

Federer also congratulated his opponent on a phenomenally successful year. He said, per Henson: "It is never fun on the not winning side, it is better than not playing at all like last year.This week was great, there were some crazy points tonight, but like plenty of times this year Novak deserved it. Well done on a crazy good year."

The pair earned but failed to take break points in the opening two games of the match, but Djokovic drew first blood, as he broke Federer in his second service game when the Swiss star netted a forehand.

With Djokovic tending to fare better in the longer rallies, Federer opted for a change of tack with some sliced backhands. At 3-2, he earned a vital opportunity to break back, but as tennis writer Jose Morgado noted, the 34-year-old was unusually careless, and it cost him:

From there, the set followed serve until at 5-3, the Serbian earned two set points. A long forehand from Djokovic handed Federer a slim lifeline, but an unforced error from the Swiss maestro on the volley gave the Djoker the lead.

As Morgado noted, neither player matched his considerably high standards:

Tennis analyst Craig O'Shannessy felt a sense of deja vu at the encounter:

Commentator David Law noted the omens were not good for Federer, who has only ever beaten Djokovic once after going a set behind.

As TennisTV demonstrated, there were still moments of exceptional quality, even if they were not as frequent as one would expect:

A series of fairly comfortable holds kicked off the second set, though Djokovic slowly began to exert more control over the court and generally looked far more relaxed than his opponent.

With the score at 4-3 to Djokovic, the Serbian raced to a 40-0 lead and earned three break points. However, the Swiss star showed magnificent resilience to win five consecutive points with some much-improved serving and hold against all odds.

The Djoker got another chance as Federer served to stay in the tournament, though, as the Swiss star afforded him two match points after yet more unforced errors into the net.

A missed forehand gave Federer the briefest of respites, but a double-fault sealed his fate and Djokovic's win. TennisTV shared the final stats, with the most damning number being Federer's 31 unforced errors:

Djokovic's victory wraps up an incredibly successful 2015 in which he won 11 titles and three of the four Grand Slams. The 28-year-old continues to go from strength to strength, and another dominant year awaits in 2016.

As for Federer, while he wasn't nearly at his best on Sunday, the 17-time Grand Slam winner showed throughout the year that there is plenty of life in him yet, so further titles and perhaps even that elusive 18th Slam could be on the cards.