Rafael Nadal has admitted that he is still struggling for form following his first-round victory over Quentin Halys at the French Open.

The nine-time champion got his title defence of to a successful start on Tuesday thanks to a 6-3 6-3 6-4 win over the French youngster.

Despite sealing his progress in routine fashion, Nadal insists that he is still finding it difficult to play his best tennis after an indifferent few weeks.

"I'm suffering from a lack of stability with my shots, but that's the way [it is] in tennis," he told reporters. "You go through difficult moments. What is important is to handle the good moments, but also the bad moments.

"I had some up and downs during the season, [and it] is normal that can happen here. I am trying to avoid that, and I am here to try to play good tennis and to give me a chance to play well and to compete for everything. My mentality and my goal is the same always."

Nadal will meet fellow countryman Nicolas Almagro in the next round of the tournament.