PARIS -- At 6-foot-6, it's impossible for Juan Martin del Potro to go unnoticed, however hard he might try. This is a man whose hammer of a forehand draws gasps from crowds all over the world. Good luck keeping that quiet.

And yet, here at the 2019 French Open, Del Potro has been keeping a low profile, talking down his chances, and pointing to his lack of matches after returning from yet another injury -- this time a fractured patella in his right knee that kept him out four months starting in October last year.

Del Potro returned briefly in February at Delray Beach, but then doctors recommended surgery. He rejected that course of action in favor of regenerative treatment, under the guidance of Dr. Angel Ruiz-Cotorro, the Spanish doctor famous for helping Rafael Nadal, among others.

Del Potro came back again earlier this month in Madrid, losing his first match. But he ruined any hopes that he might sneak under the radar when he pushed Novak Djokovic to the limit in the Rome quarterfinals, missing two match points before losing in three sets.

Like a bear awaking from his winter hibernation, Del Potro will need time to hit full steam. But his 3-6, 6-2, 6-1, 6-4 opening-round French Open win Tuesday over Nicolas Jarry, a Chilean ranked No. 58, showed that Del Potro's level is there, even if his expectations remain low. After a slow start, he was good value for his win.

"I didn't have much energy (at first)," he said after the match, explaining his slowness in the opening set. "I had never played against [Jarry]. Also, the weather conditions and the conditions on the court (were a factor). But I lost one set. That's not so much. It's not wonderful to start a match like that. It's something I have to improve in the future. Throughout the match, I felt better. I started dictating the game."

Del Potro's resilience is legendary. Four operations on his wrists, the first on his right and three on his left, would have finished off most players -- and in 2015, Del Potro almost quit. Friends and family helped convince him to have one last operation, and four years later, he is back in the top 10. Last year, he made the final of the US Open, nine years after his victory in New York -- his lone Grand Slam title.

A semifinalist in Paris 12 months ago, nine years after he first made the semifinals at Roland Garros, Del Potro is happy to be back, happy to be playing, but still trying to tell everyone that his best form is unlikely to come here -- not yet.

Juan Martin del Potro recovered from a slow start to defeat Nicolas Jarry 3-6, 6-2, 6-1, 6-4 in the first round of the French Open on Tuesday. AP Photo/Pavel Golovkin

"Of course I wanted to be here, because it's a big tournament," he said. "I have great memories from the past. And I feel good. I think I'm playing well at the moment, but my main goal is still the knee, my health. And I'm looking forward to be 100 percent in the second part of the year, trying to change my goals on tour, and if I get there, I will be happy."

Clay is a little less brutal on his knee than hard courts, and Del Potro could yet go deep here. His second-round opponent will be No. 72-ranked Yoshihito Nishioka of Japan, a man who until this year had not been past the first round in Paris. After that, Ivo Karlovic or Jordan Thompson, hardly known as mudlarks, await in the third round. So a place in the last 16, at least, would seem entirely plausible.

If matching his semifinal run of last year is a tall order, with Dominic Thiem likely to be blocking his path, Del Potro would hardly be the first person to play down his chances and then come good. Taking the pressure off is the oldest trick in the book.

"I also surprised myself after the Djokovic match in Rome," Del Potro said on the eve of the French Open. "I played great tennis for almost three hours, very high intensity, with the No. 1 of the world, which is a very good signal looking to the future.

"But I know how far (away) is my best level and I have high expectations in the future, but not now. I want to be calm, I want to be safe as well, and this is part of my rehabilitation to get better and get 100 percent soon. So I will take this tournament with a couple of curves and play as best as I can, but I'm going slowly."

The rest of the field would do well to take note -- the sleeping giant is stirring.