Grigor Dimitrov is confident he can now take the next step in his career following his victory on Sunday at the ATP World Tour Finals.
The Bulgarian has enjoyed a breakthrough year in 2017, winning the Cincinnati Masters in August and finished the season in style, beating David Goffin 7-5 4-6 6-3 at London's O2 Arena.
Dimitrov has long been tipped for the top but has so far failed to live up to his potential.
The 26-year-old says Sunday's win has shown him that he can win on the biggest stage and believes he is now ready to challenge for Grand Slam titles.
Dimitrov told Sky Sports News: "I've put myself in very good positions before, semis, finals of big tournaments and have just never been able to win.
"This year, in particular, I think I have jumped over that barrier a little bit more, playing a little bit more loose, a little bit more confident so there are a lot of things that are starting to come together.
"I don't feel like there are many other things that I've changed, it is just the constant work that I have been putting in and the results are here right now."
tagged in ATP World Tour Finals