Already the youngest player in the world top 30, Bulgarian rising tennis star Grigor Dimitrov expects the demanding approach of Australia’s Roger Rasheed to drive him higher.

And to help him turn around a disappointing grand slam record.

The boyfriend of Russia’s Maria Sharapova, the 22-year-old made almost $1 million in prizemoney last year.

He has climbed to No.23 in the rankings, helped by his maiden ATP title, in Stockholm in October, just days after teaming up with Rasheed.

Dimitrov is unsure exactly how much credit his new coach deserves for that breakthrough.

But he is certain the Australian, whose former charges include Lleyton Hewitt, Gael Monfils and Jo-Wilfried Tsonga, is making him a better player.

“He has a very strong personality,” the Bulgarian told AAP on Tuesday.

“I need someone to really keep me on a good way and work hard throughout all the days.

“It doesn’t matter if it’s Saturday or Sunday, you know you’re going to get on the court or you’re going to get in the gym and do the weights that you have to.”

Dimitrov said his association with Rasheed had also helped mentally.

“He has this strong aura that he strongly believes in things and he’s a very positive person in general,” he said.

“That definitely helps a lot.

“Coming out on court that brings extra confidence.”

Dimitrov said it was too early to predict whether Rasheed’s influence would pay off at this year’s Australian Open.

But he does expect it to bear fruit at grand slam level eventually.

Dimitrov has been past the second round just once in 13 grand slam events and was a straight sets first-round loser at Melbourne Park last year.

“I’m going to have a bit of a different approach this year,” he said.