Only one story crafted in men's tennis this year can compete with the compelling saga Andy Murray authored in the second half of 2016. That was the narrative created by Novak Djokovic. Call it the great unraveling.

The final chapters in both tales were written Sunday, when Murray and Djokovic met in the ATP World Tour finals, the first time both participants in the final match of the year would determine the year-end No. 1 ranking. Murray won it 6-3, 6-4.

It was a happy ending for Murray and, of course, a doleful one for Djokovic -- for he just hasn't been the same player in the second half of 2016.

"Tonight, Andy and I were both part of history," Djokovic graciously allowed on court during the trophy presentation. "He's the best player in the world; he's No. 1 and deserves it."

Before the halfway mark in June, Djokovic completed his historic career Grand Slam at the French Open, giving him possession of all four major titles.

Novak Djokovic won only a single title after the French Open this season. Julian Finney/Getty Images

By that time, Djokovic's rankings lead over No. 2 Murray had swollen to about 8,000 points, which is four Grand Slam singles titles' worth. But soon thereafter, things went sideways on Djokovic. Just as talk of a calendar-year Grand Slam was beginning to rev up, Djokovic stumbled out of Wimbledon in the third round. He had just one good tournament, at least by the standard he has set for himself, after that.

Elements of the great unraveling seem like fodder for a book on "life lessons." After his Wimbledon loss, Djokovic alluded to "personal problems." Those weren't the kind of difficulties that would generate a lot of sympathy from most people, but they did lead to Djokovic doing some serious soul-searching. He spoke about "evolving" as a human being, but he also began backsliding as a tennis player.

The theory, often advanced by Djokovic himself, had been that his life was extremely well-balanced, even as it was dominated by his ambitions in tennis. It had begun to fray. He took losses. They were marked by anxious, impatient or unexpectedly inconsistent play. He didn't win a singles title after the Canada Masters, where a kind draw kicked up nobody more threatening than No. 6 Kei Nishikori in the final.

The Summer Olympic Games is where the great unraveling really picked up pace. A fervent Serbian patriot, Djokovic was unlucky to draw Argentina's resurgent Juan Martin del Potro in the first round in Rio de Janeiro. Djokovic wept after he was beaten in two tiebreakers and laid the blame partly on an injured wrist. But that wrist had been able to get him into the two tiebreakers that he lost.

"I've just been through so much emotions in the first six months," Djokovic said in his postmatch press conference in Rio, reflecting on the French Open win and a loaded calendar. "I needed some time to really take it all in, digest it. But I didn't have that time. I had to a few weeks later be on the court right away. I guess that all had its toll."

Through the early fall, it remained difficult to imagine Djokovic in true danger of losing his preeminent place. But even as Murray closed in, Djokovic stuck to his lean schedule, playing just the two Masters events, while Murray piled up the wins. It might have been a strategic mistake.

Murray discouraged talk of his chances to earn the No. 1 ranking, until he had it in the bag after winning the Paris Masters. He insisted it wasn't a goal. If he had a window, he frequently said, it might be in the early part of 2017. He kept reminding everyone that Djokovic was the most dangerous indoor hard-court player on earth and the favorite to win the World Tour Finals for an outrageous fifth consecutive time.

And though Murray kept winning, Djokovic did nothing. In his spare time, Djokovic brought in Pepe Imaz, a Spanish gurulike apostle of "peace and love" who had once played in the tennis minor leagues. His influence over Djokovic now is considerable. (In his news conference on Sunday, Djokovic declined to address the future of his coaching relationships with tried-and-true confidants Boris Becker and Marian Vajda.)

Still, Murray's prospects were grim. He was a tepid 11-11 at the Tour Finals and had escaped the round-robin stage just twice. (He had never made the final.) All Djokovic had to do was earn one more win than Murray in London, whether in round robin or later, and he would close the season as No. 1.

Going into last week, Djokovic led the rivalry 24-10 and had never lost to Murray on indoor hard courts (5-0). As the week unfolded, Murray kept up in the win column, but he struggled through what became two of the three longest three-set matches played on the ATP tour this year -- the longest (3 hours, 38 minutes) the day before the final.

Djokovic, meanwhile, lost the first set he played in London, then he crushed everyone and everything in his path through the semis.

But against Murray, Djokovic's confidence sputtered. The few times it looked like Djokovic might get traction, Murray threw oil under his wheels or Djokovic slid back.

"It's required from a player to come out on the court in these particular occasions, playing top guys, to come out with his top game," Djokovic said. "I wasn't closest to that. There was no serious chance for me to win today's match. From the very beginning, we could see that."

It's a strange confession, especially the last sentence. It sounds as if Djokovic was resigned to the outcome long before such pessimism was justified.

Cop-out, burnout -- or a little bit of both? Has the great unraveling ended?

Djokovic has plenty of time now to digest what happened in 2016, but just how it will sit in his stomach is easy to imagine.