PARIS -- For an insight into the mind of Rafael Nadal, it is worth remembering something he said several years ago. It was the 2012 Australian Open, and Nadal, who was already through to the final, was asked about Andy Murray's loss to Novak Djokovic in the other semifinal, a match in which the Briton had led two sets to one.

Murray had the momentum, but mentally he eased off ever so slightly, and Djokovic raced through the fourth set. Although the decider was close, Murray was beaten -- and at that stage, questions arose as to whether he would ever win a Grand Slam title.

"Winning two sets to one, winning the third set, probably losing a lot of chances, and then winning with 7-6 -- to win a tournament like this and to play against player like Djokovic, you cannot start the fourth set like this," Nadal said.

"It's the moment to play with more intensity than ever, not start with 3-0 down and two breaks in five minutes. That way you lose the match. You want to win the tournament. ... You can lose, the other [player] can beat you, but you cannot lose in the beginning."

Intensity. Nadal's ability to work for every single point, no matter how well he is playing, has been one of the hallmarks of his career. But it is the effect that it has on his opponents that is so important. Dominic Thiem played brilliantly in the first set of the 2019 French Open final on Sunday and lost it, 6-3. He played even better to win the second set, 7-5, but the fact that Nadal stayed close throughout meant that when Thiem had the slightest of dips at the start of the third, Nadal was there to take advantage. Nadal cruised to the third set, 6-1, then took the fourth by the same score to secure his 12th title at Roland Garros.

"Dominic dropped his level a little bit and Rafa was able to play confident again, and that was key," Carlos Moya, the former French Open champion who took over as coach from Nadal's uncle, Toni Nadal, last year, told a small group of reporters after the match. "When he broke that serve with a bad game from Dominic [to start the third set], we realized that the match was Rafa's again."

Best Record in Grand Slam Final Rafael Nadal's 12-0 record in French Open finals is by far the best in a major final by a men's player at a single tournament in the Open Era. Player W-L Major Rafael Nadal 12-0 French Open Pete Sampras 7-0 Wimbledon Novak Djokovic 7-0 Australian Open Bjorn Borg 6-0 French Open

When Rafa was young, Toni Nadal stressed the importance of discipline to his nephew, famously telling him that if he broke his racket, it was a sign of disrespect to people who could not afford to buy them. Nadal's character and never-say-die attitude are the same today as they have always been.

"He always played with a big intensity," said Toni Nadal, who arrived in Paris in time for the final. "The effect was always important because when you see someone who wants to arrive at every ball, who wants to hit the ball hard, then the opponent knows. I remember when he was on court [as a child], and, for example, his father said, 'You don't need to go for this ball because you cannot [get] it,' and I said, 'No, no, no, it's better to go because then the opponent knows that when he doesn't make a wonderful shot, the point is for Rafael.'"

Where does that intensity come from? Even Toni doesn't know, although he pointed to his heart and said: "I think it is natural for him," before quoting Picasso's famous line: "Inspiration exists, but it has to find you working."

"It's [the same] for a painter, a sportsman, a journalist, everyone," Toni said. "Inspiration is good, but it's the work."

After splitting the first two sets against Dominic Thiem in Sunday's French Open men's final, Rafael Nadal turned up the intensity to take over at the start of the third. THOMAS SAMSON/AFP/Getty Images

Thiem had said he would be fine physically, even as he played for a fourth day in a row after being dealt a rough hand because of rain, wind and scheduling issues. Only he will know how much it affected him. Thiem played better than in last year's French Open final against Nadal, and he will take some solace from being only the fourth man to even win a set against Nadal in his 12 finals here. And yet Thiem was dispatched, ground down, bruised and battered by a man who has never lost a semifinal or final at Roland Garros and whose record here now reads 93-2.

Like any player, Nadal can be beaten and he can be vulnerable -- as he was at the start of the clay-court season, and as he still was when he arrived in Rome last month, still yet to have won a title this year after having had more trouble with his injured knee in March.

"Honestly, after Indian Wells (when he pulled out before his semifinal match against Roger Federer with a knee injury) ... mentally I was down. Physically and mentally, but for me, I always put more attention on the mental side," Nadal told reporters Sunday after his victory. "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, another, and then sometimes you are groggy.

Most Titles at a Single Major Rafael Nadal becomes the first male or female player in tennis history to win 12 titles at a single Grand Slam, breaking a tie with Margaret Court. Player Titles Major Rafael Nadal 12* French Margaret Court 11 Australian Martina Navratilova 9 Wimbledon * 12-0 in French Open finals

"[At Monte Carlo and the beginning of Barcelona in April], I was not enjoying [it] and too much worried about the health and, being honest, too negative. After the first round in Barcelona, I was able to stay alone for a couple of hours in the room and think about it and think about what's going on, what I need to do. ... I think I was able to change and was able to fight back for every small improvement that I was able to make happen."

Victory in Rome restored Nadal's confidence, and at Roland Garros he remains virtually unbeatable, his mind still unrelenting.

"It was really hard," Moya said. "He really had to push himself to the limit to be back on the court, to practice, to be motivated. He had unbelievable attitude in those moments, and that's what took him here today. Hats off to what he's done this month and a half, because it's easy to play well when things are working well, but what he's been through these last couple of months is showing what a competitor he is, and that mentally he is a genius."

When the stadium announcer introduced Nadal before the final Sunday, reading out his wins here -- from 2005 to 2018, with only two losses along the way -- the crowd began clapping before he could even finish.

At age 33, winning Grand Slams won't get any easier. But while the body holds up, the mind will forever be willing.