Bulgaria’s Grigor Dimitrov became the first man for 19 years to win the ATP Finals on his debut appearance with victory over Belgian David Goffin.
Sixth seed Dimitrov, 26, claimed the biggest title of his career as he won 7-5 4-6 6-3 at London’s O2 Arena.
The Bulgarian collected £1.9m in prize money for coming through the tournament unbeaten in five matches across the group stage, semi-finals and final.
He will end the year ranked third in the world, with Goffin up to seventh.
“I’m still trying to think about what I just did,” said Dimitrov, who follows in the footsteps of Spain’s Alex Corretja, who won the season-ending title on his debut in 1998.
“This is a great, unbelievable achievement for me, but I still have a lot to give.
“One of my main goals is to win a Grand Slam tournament. This has always been a dream of mine. Now, slowly, I think [I’m] getting there.”
Injuries to Andy Murray and Novak Djokovic kept two of the sport’s biggest names out of the ATP Finals, while world number one Rafael Nadal was forced to pull out injured after his opening round-robin match and Roger Federer was stunned in the semi-finals by Goffin.
But Dimitrov said it was too soon to say a new era was coming to tennis.
“Next year I think is going to be obviously pretty interesting, especially the beginning of it,” he said. “There’s still quite a few names that are going to come back and play. You should never count them out.”
He added: “Am I one of those guys? Well, right now I’m right here. I’m the winner of the tournament. But that’s about it.
“The important thing is just to stay on the ground and put your head down, even work harder because once you get to that point, everything becomes so narrow for you.
“I don’t want to get too hyped up because I’ve done well, now I’m number three in the world. This makes me even more locked in, more excited about my work, and for what’s to come.”
While Dimitrov’s season is now over, Goffin will try to help Belgium to a first ever Davis Cup victory against France next week.
“It was a special week for me,” said the Belgian. “A week with a lot of emotion and a lot of fatigue. Now I am feeling tired but it was an amazing week.”
Finland’s Henri Kontinen and Australian John Peers, the second seeds, retained the doubles title they won last year with a 6-4 6-2 win over top seeds Lukasz Kubot of Poland and Brazilian Marcelo Melo.
Dimitrov had thrashed Goffin for the loss of just two games only four days earlier in the group stage, but the Belgian proved a far tougher opponent in the final.
Goffin beat top seeds Nadal and Federer on the way through, and he made the early running as the underdog once again.
Dimitrov had to recover breaks of serve twice in the opening eight games but moved ahead when he converted a fifth set point in game 12.
After five breaks of serve in the first set, the second was a much tighter affair, with Dimitrov missing out on a potentially decisive break in game six after a Hawkeye challenge.
Goffin grabbed his chance in the next game with a forehand winner and confidently served out the set to force a decider.
The final set was a thrilling contest in itself, with Dimitrov fending off four break points in the first game before moving 4-2 up when Goffin sent a backhand long.
With two hours on the clock, and the large Bulgarian contingent chanting “Grigor, Grigor”, their man edged to the brink of victory, only for Goffin to serve his way back from 0-40 and three match points down.
The Belgian was given a huge ovation by the 18,000 spectators inside the O2 Arena, and he fended off a fourth match point, before Dimitrov finally sealed it when Goffin dumped a seemingly unmissable drop volley into the net.