Despite Walkover, the WTF Win Solidifies This as the Novak Djokovic Era

It was a disappointing end to a lackluster ATP World Tour Finals on Sunday, as Roger Federer was forced to withdraw with a back injury, thus making Novak Djokovic the winner by a walkover.

However, the unfortunate ending shouldn't take away from Djokovic's accomplishment. He won his third straight WTF title (his fourth overall) and clinched the year-end No. 1 ranking for a third time in four years.

Djokovic might be the third-best player (in a historical sense) playing right now, but make no mistake about it: This is the Djokovic era.

When he clinched the year-end No. 1 ranking after his win over Tomas Berdych in the final round-robin match of the week, Djokovic spoke to the press about why this accomplishment meant so much to him, via ASAP Sports:

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As I said, one of the highest and most difficult challenges is to be No.1 nowadays, especially because the tennis has become very competitive in the last five, ten years, very physical. To have a shot at No.1 of the world, you need to be consistently healthy and successful throughout the year.

Because Nadal and Federer are so good for so many years, they always make you win at least one or two Grand Slams if you eventually want to be No.1, and of course with consistency, because they've been so consistent with their results. 

I know how difficult it is. It's why I'm proud of this achievement.

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Despite his great successes, Djokovic is often in the shadows due to the fact that he plays alongside two of the greatest players in tennis history, Rafael Nadal and Federer. But he's proved over the last four years that he's not just a footnote or a supporting player in this era; he's a co-star.

Kirsty Wigglesworth/Associated Press

Let's break things down. Djokovic has seven Slam titles, which notably trail Nadal's 14 and Federer's 17. He is the only one of the three who hasn't won a Career Slam—he's made two French Open finals but lost to Nadal both times.

However, since the start of the 2011 season, Djokovic has been the standout. He has six major wins and 11 major finals. Nadal has five wins and nine finals, and Federer has one win and three finals.

Djokovic has now tied Nadal with three year-end No. 1s (Federer has five) and is up to 120 weeks at No. 1 all since 2011. That's significantly lower than Federer's history-making 302, but he's creeping very close to Nadal's 141.

People clamoring for asterisks will point out Federer's advanced age and Nadal's injuries over the past few years, but it's not like either one of those guys has been irrelevant over that timespan—anything but!

Douglas Robson of USA Today Sports examined the merit of the Djokovic era earlier in the week and talked with John McEnroe about the label: 

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Asked if this was Djokovic's era, McEnroe marveled that such a notion could be raised considering No. 2 Federer and No. 3 Nadal remain so relevant.

'He's done an incredible job of becoming the person that you could even ask that question when Roger is still around playing as well as he is and Rafa playing that well,' said McEnroe, a seven-time major winner like Djokovic. 'That shows you that to me he is becoming one of the true greats of all time,' and, he joked, 'another guy that's passing me.'

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It's been a memorable season for Djokovic but not a perfect one. After he won Wimbledon and regained the No. 1 ranking (oh, and got married), he struggled a bit during the summer, losing early in Cincinnati and Canada before falling in the U.S. Open semifinals to Kei Nishikori.

But this fall he has found his elite form again. He won titles in Beijing and Paris and extended his winning streak on indoor hard courts to 31. (Oh, and he became a father.)

Jacques Brinon/Associated Press

This week at The O2 arena in London, Djokovic reigned supreme. The Serb only lost one set all week, and most of the sets he played weren't even competitive. He served up three breadsticks and two bagels in nine sets of tennis.

Nobody wants to see such an elite tournament end on a walkover—not even Djokovic—but that doesn't make it any less of a coronation.

Nadal and Federer are two of the best tennis players of all time, but right now, Djokovic is outshining them both.