Wednesday 23 November 2016 13:12, UK
Andy Murray ended the year as world No 1 after a dominant victory over Novak Djokovic in the ATP World Tour Finals decider in London on Sunday.
But the week produced more storylines than just the race to be the best player on the planet.
Here, we pick out the key conclusions from the O2…
Sunday's final was not simply a match to decide who would win the title and end the year as world No 1. It was a glimpse into the sport's immediate future and a test of whether Murray is capable of staying top of the rankings in the coming years.
After several months of patchy form, Djokovic had looked back to his imperious best on his route to the final and although his level dropped considerably over the following one hour and 42 minutes, the ruthless manner in which Murray dispatched him 6-3 6-4 suggested a tennis axis has shifted.
Murray was fatigued and under immense pressure, yet he outplayed Djokovic to such an extent that it seemed he has not only met the standard required to be No 1, but raised it. A period of domination potentially beckons.
Djokovic's rapid and clinical progression to the final was so impressive that many analysts tipped him to beat Murray and snatch back the world No 1 ranking, but those predictions fell flat in a nervous and error-strewn performance that the Serb himself described as "very poor".
Djokovic held a 24-10 head-to-head record over Murray going into the match and had beaten him in two Grand Slam finals this year, so such an abject display suggested he is not yet over his struggles of the past five months.
However, Djokovic remains one of the fiercest competitors currently active in any sport and is close enough to Murray in the world rankings to make a fightback in 2017 more than feasible.
Murray may have taken the title and the acclaim, but it shouldn't be forgotten how close he came to being knocked out in the semi-finals, when he fell a set and a break down to Milos Raonic and then had to save a match point in the third-set tie break.
Raonic also gave Djokovic a scare in the group stages, losing in two tie breaks, and although his record at the tournament was only two wins and two defeats, his results were good enough to lift him to No 3 in the world.
Of more significance, however, were the pedigree of his performances. His serving and groundstrokes were unplayable at times, and if he can just become more adept at moving forward to the net, he could become as big a threat to Murray's No 1 ranking as Djokovic.
Another player who impressed at the O2 was 23-year-old Austrian Dominic Thiem, who was effectively a wildcard entry taking the place of the injured Rafael Nadal.
He defeated Gael Monfils in three sets, took a set off Djokovic and forced Raonic to a tie break in an impressive week's work that hinted he is the most exciting young player in the sport and could mature into a Grand Slam winner.
They are former No 1s who together once dominated the sport and later formed part of the 'Big Four' with Murray and Djokovic, but Nadal and Roger Federer now find themselves down in ninth and 16th in world rankings respectively.
Their fall has been largely due to injury, but with Murray having raised his level, the likes of Raonic coming through and Stan Wawrinka now regularly winning Slams, the road to returning to the top four - let alone world No 1 - looks a long and tough one.
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