Grigor Dimitrov proves he does have tennis X-factor after beating David Goffin in the ATP World Tour Finals

GRIGOR DIMITROV has proved it at last: he DOES have the tennis X-Factor.

Dimitrov thanked his girlfriend, talent show judge Nicole Scherzinger, after claiming the biggest title of his career by beating David Goffin 7-5 4-6 6-3 to win the Nitto ATP World Tour Finals.

The Bulgarian was tipped years ago to be the next big thing and earned the nickname “Baby Fed” because his style of play was a decent cover version of Roger Federer’s greatest hits.

But Dimitrov, 26, has only started hitting the high notes this year, winning his first Masters title in Cincinnati in August and now adding what is regarded as the “fifth Grand Slam”.

Dmitrov said: "I feel pretty amazing right now.

"One person who played an important part is my girfriend . She is hiding somewhere.

"She deserves quite a bit of the credit for the last two weeks."

It seemed as though the seats which might have been taken by Federer fans expecting to see him in the final had been filled instead by Bulgarians.

The unexpected climax to the ATP season was a compelling match and the first O2 final to go to a deciding set since Federer beat Jo-Wilfried Tsonga in 2011.

So it was fitting in a way that “Baby Fed” Dimitrov came through to win, breaking Goffin in the sixth game and then holding his nerve to clinch the title on his fifth match point.

The Belgian runner-up will try to take his form into this weekend’s Davis Cup Final against France.

But Dimitrov will wake up this morning, not only presumably sharing a bed with Nicole Scherzinger but also knowing that he is the No 3 tennis player in the world in the new rankings.

Where did it all go wrong, Grigor?