Novak Djokovic returned to the ATP Tour with an "ugly" straight-sets win over Ivan Gakhov at Monte Carlo and while the world number one has had extended preparation on clay this year he said he needs more time to adapt to the surface.

Djokovic, who is not vaccinated against COVID-19, was unable to play at Indian Wells and Miami last month as he failed to obtain a waiver to enter the United States.

He spent the time training on clay ahead of the French Open, where he will target a 23rd Grand Slam, but the Serbian's 7-6(5) 6-2 win over Russian qualifier Gakhov on Tuesday showed he needs more time to get into a rhythm.

"Throughout my career I needed one, two weeks of tournaments to really start to play the way I want to. It's the case again this year, though I trained for three weeks and felt good playing practice points," Djokovic told reporters.

"But it's different when you play a match, especially today (Tuesday) was quite windy on the court, so not easy to find the rhythm, to have the ball right, the ball toss and playing a lefty, playing someone that has not much to lose.

"All these things play a factor in the way you feel on the court. I'm really glad I overcome the first step, because I hope things will be better and easier from this point."

The Australian Open champion said the level of his tennis was "not very high" at the moment and he was not sure when it would pick up.

"The good feelings might come as soon as the next match or later," added Djokovic, who plays Lorenzo Musetti or Luca Nardi in the third round.

"I don't know. We'll keep working on practice courts and see what happens."