Rafael Nadal celebrates after beating Roger Federer in their final match of the Italian Open earlier this month. (ETTORE FERRARI/EPA)

Given Rafael Nadal’s impressive return to form after tendinitis forced him from tennis for seven months, it’s difficult to imagine any player spoiling his bid for an eighth French Open title.

John McEnroe sputtered when asked recently to pick his favorite for the men’s title, the answer struck him as so obvious. None other than Bjorn Borg, whose record six French titles was eclipsed by Nadal last year, considers the 26-year-old Spaniard the best men’s clay-court player of all time, hailing him as “an artist” on the surface.

That said, there are ways to attack Nadal on the finicky terre battue (“beaten earth”) of Roland Garros in the view of seven-time French Open champion Chris Evert, who compiled an unparalleled 125-match clay-court winning streak during her Hall of Fame career.

They’re the same tactics Evert would recommend to any opponent of top-seeded Serena Williams, as well, when the season’s second major gets underway Sunday in Paris.

In short: Coax Nadal and Williams to the net with drop shots (neither boasts an exceptional volley) and hit slices and short angles to disrupt their rhythm and take the punch out of their punishing groundstrokes.

“You’ve got to take them out of their power zone, right?” said Evert, who will provide commentary for ESPN. “I think you have to bring [them] in.”

Having a game plan is one thing. Having the guts and grit to stick with it against Nadal and Williams, two of the game’s hardest sluggers and fiercest competitors, is another thing entirely — particularly on clay.

Slower than hard courts or grass, clay-court tennis demands patience and fluid movement, including the timing and grace to slide to where the ball will be. It comes naturally to Nadal, who was weaned on the surface and seems to draw strength from it.

For Williams, like most Americans, playing on clay was an acquired skill. It remains her weakest surface, muting her booming first serve and giving opponents an extra split-second to gird for her blasts from the baseline. That’s largely why the French is the only major Williams hasn’t won more than once, her lone victory coming in 2002.

But Williams has been so dominant since reclaiming her No. 1 ranking in February, the surface hardly matters. She arrives in Paris on a 24-match winning streak, having claimed four consecutive titles — the last three on the clay of Charleston, S.C., Madrid and Rome.

“The level she’s at when she’s playing well, I don’t think anybody can beat her,” said McEnroe, 54, who will provide commentary for the Tennis Channel.

Nadal returned to competition in February, skipping the London Olympics, 2012 U.S. Open and this year’s Australian Open to give his left knee a chance to fully recover from another bout of tendinitis. Since then, he has posted a 36-2 record, winning six of the eight tournaments he has entered, including five clay-court titles.

At Roland Garros, the Spaniard’s record is 52-1. His only defeat came in 2009, to Sweden’s Robin Soderling, when he was fending off knee ailments and quietly grieving his parents’ divorce.

In McEnroe’s view, only top-seeded Novak Djokovic has the quickness, power, variety of strokes and mental resolve to pose a threat to Nadal. So it’s a pity that they’ve been placed in the same half of the draw, on track to meet in the semifinals rather than the final.

Though 15-19 against Nadal, Djokovic beat the Spaniard on the clay of Monte Carlo in April. The French is the only major Djokovic hasn’t won. A finalist in 2012, he fell to Nadal in four sets.

With second-ranked Andy Murray withdrawing to rest an ailing back, that gilds a path to the final for 31-year-old Roger Federer. The Swiss extended his record haul of major titles to 17 with his Wimbledon triumph last summer. Should he reach the French Open final, he’d rather face Djokovic (against whom he’s 3-3 on clay) than Nadal (against whom he’s 2-13 on clay.)

In the women’s field, the only credible opponent Williams has is herself. Her serve is the best in women’s tennis. Precious few can match the power from the baseline. And in most cases she has won the mental match before the first point is contested.

Said Evert: “I think 99 percent of the players go out there knowing that they’re going to lose.”

Two notable exceptions are Maria Sharapova and Victoria Azarenka, former No. 1 players with major titles on their résumés. Despite their power and big-game experience, their records against Williams are dismal: Azarenka is 2-12; Sharapova, 2-13.

What remains, then, is belief in themselves and the hope that Williams will come out uncharacteristically flat, as she did in falling in the first round of last year’s French Open to Virginie Razzano.

“When you get older, as Roger Federer is finding out the hard way, you have more off days because you’re not as mentally fresh as you were when you were 21,” Evert said. “My last two years that I played, I’d wake up in the morning and I didn’t want to get out of bed. I dreaded knowing that I had to go out there and play a match. That happened not frequently, but once in a while.”