What next for Dimitrov?

As Grigor Dimitrov stood centre stage holding aloft the gleaming ATP Finals trophy and the tickertape rained down on Sunday it felt like a weight had finally been lifted from his shoulders.

It was not the grand slam title he wants most but the next best thing and it felt like a breakthrough moment for a player widely perceived as one of the game's under-achievers.

He played calmly and intelligently to beat Belgium's David Goffin 7-5, 4-6, 6-3 in a superb climax to the season.

Back in 2008 the Bulgarian won the junior Wimbledon title against Henri Kontinen, who won the doubles crown at the O2 Arena on Sunday, and it was not long before he was being dubbed the natural successor to Swiss great Roger Federer.

The 'Baby Fed' tag proved a burden, however, and Dimitrov, despite occasional forays into the upper echelons of the ATP rankings, could never consistently deliver results.

In 2014, when he beat reigning Wimbledon champion Andy Murray on Centre Court, it seemed he was ready.

Dimitrov's run to the semifinals at the All England Club meant he cracked the top 10 for the first time. But it proved a false dawn.

Two years later his relationship with Maria Sharapova was of more interest than his tennis and he had slipped down to 40.

Something has clicked though and Dimitrov, now 26, began the year by reaching the Australian Open semifinals and this time he has backed it up with the most consistent year of his career.

After qualifying for the ATP Finals for the first time, he swept through his round-robin group unbeaten, fought off a ferocious challenge from American Jack Sock in the semifinals and on Sunday he overcame Goffin to claim the trophy.

He will end the year as world number three  - behind only Rafael Nadal and Roger Federer  - but crucially Dimitrov believes he is now 'locked-in' for an assault on grand slams.

"The important thing is just to stay on the ground and put your head down, work even harder," Dimitrov told reporters.

"I just want to keep the same line. I don't want to get too hyped up because I've done well, now I'm number three in the world. No, this makes me even more locked in, more excited about my work, and for what's to come.

"Right now it's a great platform for me to build on for next year. It's going to be amazing in the off-season. I know what I have to do in order to do good."

Dimitrov, coached by Murray's former hitting partner Daniel Vallverdu, is only the second ATP Finals debutant to win the title since John McEnroe defeated Arthur Ashe in 1978.

Yet rewind two years and he was struggling to play three good points in a row, let alone challenge for big titles.

Out of adversity, however, Dimitrov has finally realised what it takes to put the puzzle together.

"With the right mindset, right people, the right support, things happen. That period really helped me a lot," he said.

"I think I needed that. Those six months were a complete struggle for me. In that moment I realised what I needed to work on, who are the real people around me.

"Little by little, drop by drop, here I am."