Roger Federer found himself down match point in his tussle against Gael Monfils earlier this month in the Madrid Masters, just his second match in his first clay-court tournament in three years. At that point, Federer remembers telling himself, "Panic mode is switched on and we are coming in."

Although Federer missed his ensuing first serve, he rushed the net behind his second, catching Monfils -- and probably everyone watching -- by surprise. He went on to win the point and, eventually, the match.

It was an apt symbol of the kind of risky, aggressive tennis that makes some believe that, despite his long absence from clay, his age (37) and formidable rivals (including "King of Clay" Rafael Nadal and top-ranked Novak Djokovic), Federer can contend at the 2019 French Open. He has won the Grand Slam event only once, due largely to the dominance of 11-time champion Nadal.

Federer has frequently said he came back to the clay circuit for the sheer joy of playing on the surface on which he developed his game, and partly out of nostalgia for certain events and cities. He says he has set no goals, but this is not a man likely to feel satisfied with one or two wins at the French Open.

"[It's] a bit of the unknown," Federer said in his pre-tournament news conference in Paris on Friday. "I feel like I'm playing good tennis, but is it enough or is it enough against the absolute top guys when it really comes to the crunch? I'm not sure if it's in my racquet. ... But I hope I can get myself in that position deep down in the tournament against the top guys."

Federer withdrew from the Italian Open, the last major tune-up for the French Open, a day after playing two matches thanks to a rain-induced washout. But he said Friday the leg pain that forced his withdrawal was gone. "There has always been little things going on, like in Rome," Federer said. "But that was also precautionary. I wanted to make sure I was 100 percent going to be able to play the French Open."

So, what have we learned about the state of Federer's clay-court game? And what chance does he have of making a major impact over the next two weeks at Roland Garros?

Using the four matches he played in Madrid and Rome, plus his opening straight-sets win against Lorenzo Sonego, as a guide, here are five key areas where the answer will be determined.

Serve

Federer's first-serve percentage and ability to serve and volley could be key to his French Open success. Clive Brunskill/Getty Images

It's a truism, but more relevant to Federer's fortunes than to those of others: You live and die by your first serve. Although his ace count is relatively modest, Federer mixes and hits his locations with great precision. That first serve keeps opponents off balance. As Dominic Thiem, who had to rebound from losing the first set and won in three sets over Federer in the quarterfinals at Madrid, said after the match: "He was serving very well. I had big troubles with the return until the third set."

Only three players -- John Isner, Milos Raonic and Sam Querrey -- can top Federer's 80.3-percent success rate on first-serve points, yet Federer is ranked a lowly No. 17 in aces per match (8.3).

In the critical second-set tiebreaker of that Madrid quarterfinal, however, Federer was unable to hang on to an early mini-break and also presented Thiem with his first set point because Federer couldn't put his first serve into play. That was also his undoing in the final point that gave Thiem a 13-11 tiebreaker win after Federer was unable to convert either of two match points.

Unlike so many of his peers, Federer is comfortable playing serve-and-volley tennis on all surfaces, including clay. But the effectiveness of the tactic can vary from event to event, and even day to day.

"It is an option to be used on a hot and sunny day in Paris too," Federer said of his willingness to follow even second serves to the net. "I always thought that serve and volleying on a hot day on clay almost has more reward than on a grass court sometimes because the ball jumps out of the strike zone a little bit more and it's harder to press it down again into the feet of the attacking net player. So I think serve and volley can work very well on the clay."

Consistency

The idea that "consistency" on clay means the ability to play interminable rallies is outdated. The surface doesn't dictate the nature of the game -- the intentions and styles of the players do. That's why so many of the best clay matches feature thrilling five- or six-shot exchanges rather than 18-shot rallies.

Paul Annacone, the Tennis Channel analyst who coached Federer through many of his best years, told ESPN.com: "[Federer] doesn't play the quintessential clay-court tennis game, and I don't think he ever did. Even when he was making those RG finals."

Deep into the third set of his Italian Open third-round win over Borna Coric recently, Federer had won every point that had him 6 feet or more behind the baseline. His problem wasn't losing the rally game, it was in his unforced errors -- particularly on the backhand side. The more aggressive, drive version was breaking down to the point where he was making two errors for every winner he hit off that wing.

Real consistency means hitting purposeful shots while avoiding unforced errors.

Court positioning

Roger Federer at the French Open As Roger Federer makes his return to Roland Garros, here are some of the most interesting numbers from his career play in Paris, courtesy of ESPN Stats & Information: • He has 65 career match wins at Roland Garros, second most by any man in the Open era behind 11-time champion Rafael Nadal (86). • Federer has reached at least the second week in each of his past 11 French Open appearances. • Federer averaged 87.3 percent serve points won between 2009 (the year he won at Roland Garros) and 2015 (the last year he played there). • Federer has a 65-16 career record at Roland Garros and he is 55-4 overall there when he wins the first set.

To be most effective against the most dangerous opponents, Federer needs to take control of points. The easiest way to achieve that is to play up on or inside the baseline. It's a tough assignment on any surface because of the reaction time and focus it demands. Federer had plenty of energy in Madrid and Rome.

"Roger has been coming out hard and fast, the way Andre [Agassi] used to do," Gilbert, a former coach of Agassi, said of Federer's willingness to take the game to his opponents. "He's keeping rallies short, using the drop shot a little more and -- more than anything -- playing a game that makes his opponents uneasy."

Federer came out blazing in the first of the two matches he won on that rain-induced double-up day in Rome, a one-hour, 20-minute win over Joao Sousa. Federer's forehand was especially devastating, and thanks to Sousa's penchant for hanging back, Federer was able to run around his less dangerous backhand freely and frequently. Unless Federer is making a boatload of unforced errors, it's difficult to beat him if he has set himself up inside the court.

Gilbert put it this way: "An opponent has to make him do different things to have a chance. If an opponent isn't putting him on the stretch or making him play too much defense, Roger is going to be able to play his type of tennis and make opponents uncomfortable."

Against the best players, though, more will be required of Federer. He will need the ability to absorb punishment and transition from defense to offense with greater alacrity to not get sucked into long points.

The backhand

Federer's more dangerous, drive backhand let him down in his narrow escape against Coric. But the oft-heard theory that the one-handed backhand is a liability on clay is being demolished these days. As Thiem said in a news conference in Madrid: "I think if you have a very good one-handed backhand, it's not a problem. It's maybe even a little advantage on clay. Like [Stefanos] Tsitsipas or me, we can go back and we can really play so much spin with the one-handed backhand."

As expected, Federer endorsed that opinion. When dialed in, his flat or topspin backhand has been an effective weapon. But it's the slice option, including the chopped or blocked service return, that comes in so handy on clay. It's a fallback, for one thing. But slice also serves as a reset button for changing the pace of a rally. It buys Federer time to get into a better court position, and sometimes it's the safer option for threading the needle down the line.

Federer got the first break in his Rome match with Sousa thanks to a cross between a chop and blocked backhand serve return. The ball took forever to travel down the line and land gently right in Sousa's backhand corner. The shot, so unfamiliar in tennis these days, put Sousa in an uncomfortable position, and after a brief rally, Sousa made an unforced backhand error.

Variety

As Gilbert said, "Roger does everything great." The key for Federer is execution. Somewhere in all the hype about Federer's return to clay and Nadal's superiority on the surface, some have forgotten that for a long time Federer was clearly second only to Nadal on clay.

Since those days, Federer has gotten older, but he has also grown wiser. He's playing more aggressive, high-risk, high-reward tennis -- partly because swifter points mean less fatigue.

"He's up on the baseline," Annacone said. "He takes the ball early, varies his attack strategy and uses the drop shot. That's what makes him so much fun to watch, and that's what's kind of been missing at these tournaments."

Federer's serve, while always excellent, has aged well and become more precise than ever. Early in his career, Federer held the drop shot in contempt. Now it has become a useful tool. Tactically and strategically, Federer might be at his peak as a player on clay.

The challenge in the days ahead will lie in the area of execution because veterans are more susceptible to coming up flat than the young. Federer also must avoid long, knockdown, drag-out battles.

"Roger is playing fine," Annacone said. "The biggest challenge for any over-30 player is the best-of-five format, especially on clay. And that's particularly magnified by the nature of the competition, meaning Rafa and Novak."

Maintaining his fitness looms as another imperative on Federer's must-do list. "If you can avoid tough, long matches in the beginning, it's going to increase your chances for the tournament later on," he said. "Being healthy solves so many issues. Of course, winning solves everything."

Those don't sound like the words of someone who'd settle happily for a second- or third-round exit.