I was sitting on a bench a few feet from Federer, and as I watched him nonchalantly perform a shot that I was reasonably certain no other human being could pull off, I felt my mouth widen and my chin sag. I was experiencing, not for the first time, a Federer Moment. This was the term coined by the novelist David Foster Wallace to describe instances in which Federer hit shots so improbable and sublime that “the jaw drops and eyes protrude and sounds are made that bring spouses in from other rooms to see if you’re O.K.” Wallace wrote those words in 2006 for an article titled “Federer as Religious Experience,” which was published by Play, a former sibling publication of this magazine. His tribute suggested that Federer, with his telepathic anticipation and ability to create impossibly angled shots, was restoring beauty and elegance to men’s tennis. Ivan Lendl, who now coaches Andy Murray, had become the top-ranked player in the mid- to late 1980s by relying on the so-called power game. The dour Lendl didn’t have the innate talent of, say, a John McEnroe, but he was amazingly fit and had great strength that he used to generate concussive groundstrokes. Lendl planted himself at the baseline and wore down his opponents. It wasn’t pretty, but it was effective — Lendl won eight Grand Slam titles — and it fundamentally changed men’s tennis from a sport that revolved around agility and finesse to one rooted in brute force. “In the same emphatic, empirical dominating way that Lendl drove home his own lesson, Roger Federer is showing that the speed and strength of today’s game are merely its skeleton, not its flesh,” Wallace wrote. “He has, figuratively and literally, re-embodied men’s tennis, and for the first time in years, the game’s future is unpredictable.”

It was a nice thought, but it turns out that Wallace was wrong. What made the power game possible was a revolution in technology that no single player, not even Federer, could reverse. In the early 1980s, wooden rackets gave way to lighter composite graphite frames that enabled players to put more pace on the ball. Racket heads also increased in size, which added to the power while also allowing players to be a little less precise with the point of contact. In the last decade or so, natural gut strings have increasingly given way to polyester and other synthetic varieties that can put enormous topspin on the ball. All that spin allows players to take a more powerful swing and to routinely hit shots — like cross-court winners from extreme defensive positions — that were impossible a generation ago. “It is unrecognizable from the game I played,” Cliff Drysdale, a top player in the 1960s who is now a tennis announcer for ESPN, recently told me.

The tournaments have made changes that limit technology’s effects, and these have led to other consequences. The All England Club has changed its grass from a blend of 70 percent ryegrass seed and 30 percent creeping red fescue to 100 percent ryegrass. This has made the soil drier and harder, which causes the ball to bounce higher; players have more time to get to the ball, and it is subsequently more difficult to hit outright winners. Five years ago, the Australian Open changed its surface from Rebound Ace to Plexicushion, which some players have said yields a marginally slower pace. The U.S. Open is said to have added sand to the acrylic-paint mixture on its hard courts in order to slow things down, too. The men still knock the felt off the ball — at this year’s Wimbledon, the Argentine Juan Martín del Potro hit a 113-mile-per-hour forehand — but the slower courts have changed the risk-reward calculus. Given the speed and spin that players can generate, and the fact that it is now tougher to hit winners, it has become perilous to rely on unrelentingly aggressive shot making. As a result, the game has become even more anchored to the baseline. During last year’s Australian Open final, Nadal and Novak Djokovic, the current No. 1, spent nearly six hours pummeling each other from the back of the court in possibly the most arresting display of strength and stamina that tennis has ever seen.

Few players have profited more from these changes than Nadal. His forehand topspin averages 3,200 revolutions per minute and has been clocked as high as 4,900. (Federer’s forehand, by comparison, averages just 2,700.) With topspin, the ball travels deep into the court and then nose-dives — a phenomenon known in physics as the Magnus effect. What sets Nadal’s topspin apart is that the ball descends so fast that it then explodes off the ground, forcing opponents to play it at shoulder or ear level. Nadal’s cross-court forehand is difficult for anyone to handle, but it is practically Kryptonite for players who rely on a one-handed backhand. Nadal, who grew up playing on clay and is a relentless retriever, has benefited from the slower court surfaces too. All these factors might suggest why he has amassed a dominant 21-10 record against Federer, one of the few remaining players on the tour with a one-handed backhand. (Thirteen of those victories occurred on clay, Nadal’s best surface.)

For Federer, the slower conditions were a challenge. When he came on the tour, he was an attacking player. As the game slowed, though, he had to harness his natural inclination to try to quickly put the ball away; that was all but impossible now. A comparison: During a 2001 fourth-round Wimbledon match against Sampras, Federer played 109 serve-and-volley points; when he beat Murray in last year’s Wimbledon final, he played 11. “I had to become a more passive player, to keep the ball in play,” he told me at Wimbledon. “I definitely had to adjust more to the 25-shot rallies than the guys who are five years younger than I am. Thankfully, I was good enough off the baseline, too.”

That Federer was able to win 17 majors despite altering his game underscores his extraordinary talent. But it has also become clear that he has been an outlier in his own era, an artist among pugilists. Apart from Grigor Dimitrov, a promising Bulgarian who appears to have modeled his style after Federer’s (hence his nickname, Baby Fed), there is scant evidence on the men’s tour of his imprint. When I asked Federer if he saw his influence in younger players, he drew a blank. “I don’t know how much,” he said. In the end, Lendlism won.