The 22-year-old, dubbed "Baby Federer", is the latest flame of Maria Sharapova but has also attracted attention because of his impressive rise in the world rankings, from 95 a year ago to number 28 before the French Open this week.
On Tuesday, Dimitrov, seeded for the first time in a grand slam event, progressed to the second round when his Colombian opponent Alejandro Falla retired while trailing 6-4 1-0.
The Bulgarian, who used to spend his off season in sunny Dubai, said his recent success was helped by a training camp in Sweden with new coaches Magnus Norman and Mikael Tillstrom.
"Last December was one of the darkest months in my life. It wasn't easy. We had been working a lot on fitness," Dimitrov, seeded 26 in Paris, told reporters after his match on Tuesday.
"It was a period I really needed to pass through. It was a lot of hard work and a lot of dedication. But after, you feel like you have done something well and I felt good about myself."
Dimitrov began his Roland Garros campaign under unseasonably gloomy skies but it was his run-up to the event that suggested he had a bright future.
His claycourt preparation included a tight three-set defeat by Rafa Nadal in Monte Carlo then a shock victory over Serbia's world number one Novak Djokovic in Madrid.
Dimitrov could meet six-times grand slam winner Djokovic in the third round in Paris but believes he is ready.
"When you come into a tournament, you've got to be positive and loaded with energy," he added.
"Playing matches and playing good players gives you confidence. I think with every match you're starting to think: 'I can go further'.
"Then, once you have that mindset, you can win every day you come on court."
- Sports & Recreation
- Maria Sharapova
- Alejandro Falla