Grigor Dimitrov set his sights on winning his first Grand Slam after his dramatic victory at the ATP Finals on Sunday gave him the biggest title of his career.

The Bulgarian sixth seed held his nerve to beat Belgium’s David Goffin 7-5, 4-6, 6-3 in a gripping contest at London’s O2 Arena, finally sealing the match with his fifth championship point.

The victory takes the 26-year-old to the dizzy heights of third in the rankings behind only Rafael Nadal and Roger Federer as he begins to deliver on his rich promise.

Nicknamed “Baby Fed” early in his career for the similarity of style in his game to the Swiss, Dimitrov has struggled to live up to the comparison and was as low as 40th in the world in mid-2016.

But he has bounced back strongly to enjoy the best season of his career in 2017, winning four titles in all, including his first Masters title in Cincinnati.

Dimitrov has never been beyond the semi-finals of a Grand Slam, reaching the last four at Wimbledon in 2014 and repeating the feat in Australia earlier this year.

“I’m still trying to think about what I just did,” said the Bulgarian after his victory against Goffin. “I think now definitely we going to sit down with the team and reassess the whole year, see what we’ve done good, what we can improve.

“Of course, one of my main goals is to win a tournament, you know, a Grand Slam tournament. This has always been, again, a dream of mine. Now slowly I think this thing is getting there.

“I think I’ve had good results in the past, but now, as I said, I need to be even more consistent on those kind of events, and in the same time raise up my level on occasions like this. Obviously, this is a great, unbelievable achievement for me, yes. But, yeah, I just still have a lot to give.”

‘Big Four’

The ATP Finals have had an unusual flavour this year, missing Andy Murray and Novak Djokovic while world number one Nadal was forced to pull out injured after his opening round-robin match.

In a huge shock, Roger Federer was ousted in the semi-finals by Goffin.

But Dimitrov said it was too soon to proclaim a new era and write the obituaries of the “Big Four” who have dominated tennis over the past decade and more.

“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. That’s just obvious. You should never count them out.”

The Bulgarian said his win in London had lifted him into the conversation about the top players but he had to work hard to capitalise on that.

“Am I one of those guys? Well, right now I’m right here. I’m the winner of the tournament. So, yes, I’m happy with it. But that’s about it. Like, 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 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 I think locked in, more excited about my work, and for what’s to come.”