Maria Sharapova and Rafael Nadal may not have a lot in common as people—he’s "not my type,” she has joked—but their careers have run on parallel tracks. They’re both in the elite club of career Grand Slammers, both have been at their best on clay, and both have spent long periods in the shadows of another player (in her case, Serena Williams; in his, Roger Federer). They’re also both famous for their cussed competitiveness. My co-nickname for them over the years has been The Persistents. While that may sound like the world’s most boring garage band, it has made for a pretty successful duo on the tennis court.

Now, with exactly one month left before the French Open, its defending champions are both struggling. Even in their defeats on Thursday—hers in Stuttgart to Angelique Kerber; his in Barcelona to Fabio Fognini—Sharapova and Nadal seemed to be channeling each other.

Serving for the second set at 5-4, down break point, Nadal had a sitter forehand at the net. Instead of putting it away as he usually would, he drilled the ball right back at Fognini. The Italian, who hadn’t moved, snapped off a forehand pass and won the match in two.

A few hours later in Germany, Sharapova was up a set on Kerber and was serving at 5-5 in the second, down break point. Like Rafa, Sharapova had a sitter forehand at the net. And like Rafa, instead of going into the open court, she drilled the ball right back at Kerber and eventually lost the point, the set and the match. (Anyone who has watched Sharapova over the years knows this isn’t an uncommon occurrence with her.)

Maria turned 28 last week, and Rafa will turn 29 in June; they’ve both been on tour since they were 15. It may be tempting to speculate that they’ve begun to reach the limits of persistence, but it's too soon to start that discussion. Sharapova and Nadal also happen to share a long-established knack for bouncing back from adversity, digging out of slumps and leaving career-threatening injuries behind. Sharapova was coming off a leg injury in Stuttgart, and Nadal, at least according to him, is still in the process of finding his game after being sidelined for much of 2014’s second half. Neither of their losses on Thursday qualified as shockers, either—Kerber beat Sharapova at Wimbledon last year, and Fognini beat Nadal on clay earlier in 2015.

Still, those caveats aside, would you favor either Maria or Rafa to defend their titles in Paris right now? Each of them trails their tours’ No. 1-ranked players, Serena and Novak Djokovic, by a good distance at the moment. And it’s been a while since they looked anywhere close to their best.

After winning in Brisbane and reaching the Australian Open final, Sharapova has lost to Kerber, 16th-ranked Flavia Pennetta and 97th-ranked Daria Gavrilova. With her defeat yesterday, her ranking dropped from No. 2 to No. 3. The woman who traded places with her, Simona Halep, is now looking like the second-favorite, after Serena, at Roland Garros.

So far in 2015, Nadal has lost to Fognini for the first and second times; Milos Raonic for the first time; Tomas Berdych for the time in nearly a decade; Fernando Verdasco for the second time in 15 matches, and 127th-ranked Michael Berrer. Rafa is in danger of slipping back to No. 5 behind the top seed in Barcelona, Kei Nishikori.

Again, it’s too early to say for sure, but Sharapova falling behind the younger Halep, and Nadal falling behind the younger Nishikori, feels like part of a (very) gradual generational shift. It will be interesting to see what happens two weeks from now in Madrid. Last year in the finals there, Sharapova came back to beat Halep in three sets, while Nadal escaped a hot-hitting Nishikori when Kei aggravated a back injury. If they face the same opponents at the Caja Magica in 2015, again, will persistence be enough to prevail again?

As far as their form goes, Sharapova seems to have a little less to worry about than Nadal. The Russian, as noted, has had a leg injury, and Kerber, who was fired up in front of her home audience and coming off a title two weeks ago in Charleston, played some of the best tennis of her career to win the third set.

At the same time, though, Stuttgart has always set the tone for Sharapova on clay. She had never lost in three trips here before Thursday; two of those years she went on to win the French Open. Now, obviously, a different tone has been set. Kerber showed, as she showed last year at Wimbledon, how much getting the proverbial “one more ball back in play” can mean against Sharapova. For the first set and a half, Maria was immune to it, but with Kerber serving to stay in the match at 4-5 in the second, Sharapova suddenly couldn’t find the court. The German isn’t known for her serve, but Maria clanged three backhand returns well out. She never found her range again and won just one more game.

Some days, perhaps because of the risks she takes, the ball comes off Sharapova’s strings all wrong, and no amount of grit is enough to do anything about it. She hasn’t had many of those days on clay over the last four years. Now she has a month to put this one behind her.

Nadal, by contrast, finds himself in something of a familiar spot. Last year, he took a bad loss to Nicolas Almagro in the quarters in Barcelona, and left everyone wondering whether his years of invincibility on clay were finally at an end. If anything, though, the situation feels a little more desperate this time around, for two reasons.

First, in 2014, Djokovic wasn’t in the imperious form that he is today. Last year he lost to Federer in Monte Carlo and would pull out of Madrid with a shoulder injury. Today Djokovic is healthy and dominant, the clear No. 1.

Second, Nadal is struggling with his best and most essential shot, his forehand. Against Fognini, Nadal seemed to be getting too close to the ball with it; whatever the reason, the results were shots that landed short when he was in a defensive position, and landed long when he was in an offensive position. Most alarming was the forehand Rafa hit when he was serving for the set at 5-4 in the second; at 0-15, he had a look at a floating ball and somehow buried it in the bottom of the net.

“My forehand has been my biggest virtue,” Nadal said later, in what will surely be one of his most memorable moments of self-laceration. “But my forehand was vulgar, it wasn’t worthy of my ranking and my career.”

At times, Rafa’s form against Fognini reminded me of the way he played on the South American clay circuit when he was making another comeback, in 2013. His play was poor, his shots way off, and he was frustrated, yet he ended up winning most of those matches on what looked like determination alone. Yesterday, when he came back from 3-6 down in the second-set tiebreaker to make it 6-6, I thought the same thing might happen again. Fighting through those matches in South America two years ago led to a much higher level of play the following month. This time he won’t have that opportunity. He’ll have to start over again in Madrid.

Afterward, Nadal largely abandoned the “I’m on the right track” line of thought that he had used after previous losses this season. His language was starker.

“I played poorly,” he said, his body tense. “I didn’t play like I should have. This is a blow for me, but I accept the challenge and the negative day I had. There is no other way forward than to accept it or die.”

At the start of this week, I wrote that while Djokovic is in the pole position for Paris, Nadal may also be right where he wants to be—chasing, rather than being chased. It’s impossible, after this loss and his subsequent words, to think that now. The past, in the form of nine titles at Roland Garros, and three wins over Djokovic there in the last three years, is still on his side. And so, perhaps, is the future: There’s still a month to go. But Nadal hasn’t been this far from being the French Open favorite in a decade.

And that’s fine. That is, as Rafa would say, "the life" that he and Sharapova lead and the sport they play—everyone has setbacks and defeats. The careers of these two players have always been as much about the process as they have the results. And what was most memorable about their performances on Thursday wasn’t that they lost; it was, as always, their relentless effort. Why else do we watch sports if not to see athletes who care this much?

At one point, Sharapova tumbled onto the clay and lost her racquet; as she scrambled to get up, she did her best to reach out and pick up the wayward frame. She didn’t succeed, but as Tennis Channel commentator Mary Carillo said during the replay, “That says it all about her, doesn’t it?”

As for Rafa, I don’t think I’d ever seen him look as intense or intent as he did in his presser on Thursday. He left no doubt, if you ever had any, of his desire to play his best again—you accept the setback and learn from it, he said, or you die. That he can still have that attitude after winning nine French Opens says it all about him, doesn’t it?