The 33-year-old swept to an 18th Grand Slam crown with a 6-3, 5-7, 6-1, 6-1 victory over Austria's Dominic Thiem in a repeat of the 2018 final.
Nadal is now just two behind Roger Federer's all-time record of 20 majors and three ahead of Novak Djokovic who was knocked out by Thiem in the semi-finals.
However, Nadal said that his troubled season leading up to the French Open had left him facing new fears about his ability to defend his title in Paris.
“I was not enjoying it too much, I was worried about my health. I was down mentally and physically after Indian Wells,” said Nadal.
“I was too negative. After Madrid and Barcelona, I was thinking about what I needed to do. I could stop for a while and recover or change my attitude and recover.”
An emotional Nadal collects his prize. Photo: AFP
After a loss in the Australian Open final to Djokovic where he won just eight games, a second round exit in Acapulco was followed by a withdrawal from the semi-finals in Indian Wells, when a knee injury meant that an eagerly-awaited clash with Federer was shelved.
His return in the clay court season saw semi-finals losses in Monte Carlo, Barcelona and Madrid before a much needed title triumph in Rome.
“This is a very satisfying victory. In 2018, I only played nine events and finished just seven of them,” he added.
“I had issues with my knee and surgery on my foot, so many issues in the last 18 months that have made the last few weeks very special.”
Nadal revealed that in Barcelona, he had locked himself away where he ended up questioning where his season was heading.
“Mentally, I lost a little bit of that energy, because I had too many issues in a row. It is tough when you receive one after another, and then sometimes you are groggy,” he explained.
“In Barcelona, I was able to stay alone for a couple of hours in the room and think about what's going on, what I need to do.
“One possibility was to stop for a while and recover my body. And the other was change drastically my attitude and my mentality to play the next couple of weeks.
“Thinking a lot, finally I think I was able to change and was able to fight back for every small improvement that I was able to make that happen.”
— Rafa Nadal (@RafaelNadal) June 9, 2019
World number two Nadal took his Paris record to an astonishing 93 wins and just two losses having previously won the title in 2005-2008, 2010-2014, 2017 and 2018.
It also gave him an 82nd career title and 950th match win.
“All the things that I went through probably give me that extra passion when I am playing, because I know I will not be here forever.
“So I just try to be positive, to be intense, and to be passionate about what I am doing.”
Nike produced a compliation video of Nadal, beginning when he was just 16 years-old.