Rafael Nadal is adamant that Novak Djokovic's threat to his French Open domination will be no different to any other year.

World number one Djokovic has been in sensational form in 2015, lifting the Australian Open and winning three straight Masters titles - becoming the first man to win the opening three ATP 1000 events of the season.

The Serb earned a notable victory over Nadal on his favoured clay surface in the Monte Carlo Masters semi-finals last week, leading many to suggest Djokovic will complete the career Grand Slam this year.

But Nadal, who has won the title in nine of the past 10 years at the French Open, says the competition is nothing new and that Djokovic has consistently been a contender at Roland Garros.

"Djokovic was good in 2011, in 2012, 2013 as well as in 2015. Sometimes you win more and some you win less," Nadal said.

"It is difficult to win everything all the time. Djokovic was as good then in 2011 as he is now. He had an impeccable year in 2011 as well as he is having in 2015. I have to congratulate him.

"The rest of the players have to accept that at the moment he is the world number one with all he has achieved this year. 

"This year I have to do things right, get back to a very high level to face him on the court.

"Tennis-wise, I feel a lot better than a few weeks ago. I am going to try to get as far as I can and to play as well as I can, topping the level I showed in Monte Carlo."