Djokovic has upstaged Federer in the semi-finals en route to three of his championships in Melbourne and crushed Nadal in last year's decider after also denying the Spaniard in the longest grand slam final in history, the 2012 epic that stretched seven minutes shy of six hours.

The super Serb also leads Federer (26-23) and Nadal (29-26) head-to-head in two of the most compelling rivalries in tennis history.

But he doesn't believe any of the three titans - who boast a mind-boggling 55 slams between them - would be as good as they are without each other.

"We've helped each other to evolve a lot as players, to understand how we can get better, what things we can improve," Djokovic said ahead of his 2020 opener against Jan-Lennard Struff on Monday.

"So when we face each other we can be the best versions of ourselves so we can pull out the best quality of tennis that we possibly can because that's what it takes to win against each other.

"We always require the best tennis from our opponents and between the three of us I think the intensity, the anticipation before the match just obliges us to step it up and play our best because otherwise we're going to lose.

"That kind of rivalry has been really special between the three of us and has brought us to these tennis heights where we are at the moment.

"I think we still look at each other's games, look at each other's careers and still measure our own careers compared to the others.

"That's the beauty of the rivalry and I think we're contributing to the evolution of the sport."

Djokovic rates his 6-3 6-2 6-3 Open win over Nadal last year as his most complete grand slam final performance.

"Rafa was in great form, he hadn't dropped a set the entire tournament and the way I played was just amazing," he said.

"I was very proud. It's one of those days where everything just works perfectly. I was in the flow and playing my best tennis."

Djokovic completed a "perfect" preparation for this year's Open with his ninth consecutive straight-sets win over Nadal in last week's ATP Cup final.

But the second seed suspects he'll need to again be at the top of his game to fend off the next-gen challengers in Melbourne.

"Definitely Daniil (Medvedev) is playing great tennis. He played a close five-setter against Nadal in the US Open last year," Djokovic said.

"He was two sets down and it was very impressive to see Medvedev coming back strong and going over five hours.

"Those are the signals and the signs that you want to see in champion's mentality.

"So he's definitely in that small group of players that are getting closer and narrowing the gap to the grand slam title.

"Dominc Thiem has been around and knocking on the door. (Stefanos) Tsitsipas won a big title in World Tour Finals.

"So tennis is in good hands. We have a good next generation of players with (Alexander) Zverev, of course.

"We are hoping that this is not going to be the year where they win a grand slam.

"But that's inevitable. It's going to happen and, when and if it happens, it's going to be good for the sport."

Australian Associated Press