No room for sentiment, Novak Djokovic will cast friendship aside when he sets about sweeping into his 19th successive grand slam quarter-final at the Australian Open on Sunday.

Only Roger Federer, with 36 straight appearances in the last eight, can boast more consecutive grand slam quarter-final runs than Djokovic and the defending champion is vowing to have his game face on again when he takes on Italian Fabio Fognini.

The pair of 26-year-olds have known each other since their junior days.

“I’m going to try to win against him regardless if he’s friend or not,” Djokovic said.

“Of course, I respect him. I have a great relationship with him, real friend relationship for more than 10 years.

“Once we get on the court, of course we’re both professionals, we want to win.

“He’s 15 in the world. He’s been playing some really good tennis.

“He’s a claycourt specialist, so that’s where he made his best results. But lately he’s been performing really well on hard court.”

The steely Serb has wasted just five-and-a-half hours on court in powering into the second week at Melbourne Park, not dropping a set in three matches.

“That’s obviously one of the goals,” he said.

“It’s important not to underestimate any opponent. Having the right approach to the court, having the right intensity, starting from the first point to try to show to your opponent that you’re there to win, that you want to be the one taking control of the rallies.

“That’s my goal coming into every match regardless of who is across the net.”

The four-time Open champion is shooting for his 25th win in a row at Melbourne Park – and almost every one has come at Rod Laver Arena.

“This is definitely one of my most favourite tournaments in the world, the best grand slam by far,” Djokovic said.

“I love playing on Rod Laver Arena. Results are showing that.”