On this day 10 years ago, Novak Djokovic's long unbeaten streak ended, and Roger Federer's ageless genius surfaced

WATCH: The footwork of Roger Federer in ASMR.

Today marks the tenth anniversary of one of Roger Federer’s finest moments at Roland Garros. But it wasn’t his sole run to the title; that took place in 2009.

What happened two years later proved a sparkling reminder that Federer is—as is sometimes forgotten—one of the finest clay-court players in tennis history.

It was a semifinal, pitting Federer against Novak Djokovic. As that year began, here was each player’s Grand Slam tally: 16 for Federer, one for Djokovic. Starting in 2007, for four straight years, Djokovic had finished the year ranked No. 3 in the world—clearly ahead of everyone else, but constantly nipping at the heels of Federer and Rafael Nadal.

Through the last quarter of 2010, the Serb gained considerable confidence. In the semis of the 2010 US Open, Djokovic fought off two match points to beat Federer, going on to lose a highly competitive final to Nadal. He capped off the year with an emotional victory for Serbia, leading his nation to its first-ever Davis Cup title.

Once 2011 got underway, Djokovic’s commitment to a gluten-free diet and other fitness upgrades began to pay off in a big way. He dropped just one set to win the Australian Open, a run that included a victory over Federer in the semis. There followed six more titles on the road to Roland Garros, Djokovic earning two more wins versus Federer and four against Nadal, including a pair on clay.

By the time Djokovic reached the semis in Paris—without the loss of a set—his 2011 match record was 41-0. Not since John McEnroe in 1984 had a men’s player begun the year so dominant.

Federer’s start to 2011 was much less productive. Ranked second at the start of the year, he was overtaken by Djokovic in March. Losses to Djokovic and Nadal were one thing, but Federer had also been beaten in 2011 by Jurgen Melzer (for the first time in four matches) and Richard Gasquet (for the first time in nine meetings).

Djokovic was clearly the favorite. If his proficient baseline game could so vanquish Federer on hard courts, what chance did the Swiss have on clay?

Guess again. One of the many joys of Federer has been his wide spectrum of tools, an asset that allows his tennis to take on an exponentially textured and dynamic quality. Perhaps such is the case for all of tennis’ great champions, but no one has ever constructed and deployed them more eloquently than Federer. Cuts and blows, spins and paces, precision and power, layers and labyrinths: call the Federer game a spider web of the highest caliber.

Each day at a major has its own distinct feel. At Roland Garros, the Friday of the men’s semis conveys a sense that the grand clay-court carnival is nearly over, that nearly two weeks of Parisian festivities are about to reach the denouement, that all such prior matches—an early-round upset, a middle-weekend epic, an intriguing quarterfinal—are transitory, about to give way to the outcomes that will be most remembered. No matter who’s in the final four, this awareness of closure can be both sad and inspiring.

One semi that day was a mildly suspenseful win for Nadal (on his 25th birthday) over Andy Murray. Call that match the acoustic opening act. Federer vs. Djokovic, though, posed the possibility of electricity.

They began just past 6:00 p.m., in overcast conditions that heightened the awareness that Roland Garros was much closer to midnight than morning. I was working that evening in the Tennis Channel broadcast booth, just behind the south baseline. The view was fantastic, the tennis even better.

Djokovic was clearly the favorite. If his proficient baseline game could so vanquish Federer on hard courts, what chance did the Swiss have on clay?

The first set lasted 70 minutes. Federer saved two points, was down 5-4 in the tiebreaker, but snapped up three straight points to win the set—and then sprinted to a 4-1 lead in the second and went up two sets to love.

The contrast between these two was vivid, a tug-of-war pitting Djokovic’s relentless depth and movement versus Federer’s eclectic mix. The clay, even slower than usual amid this weather, compelled a triggering of the reset button in many of the rallies. It was quite thrilling to repeatedly see each man take a blow and redirect the energy of a given point.

Still, excited as the crowd was, its heart was clearly with Federer, the 29-year-old icon who’d been No. 1 for many years and by this stage reached the finals at Roland Garros four times. Djokovic had only turned 24 in late May and at that point had never gone past the semis in Paris.

Djokovic countered. He won the third set 6-3 and in the fourth served at 5-4. By now it was past 9:00 p.m. Recall that back then, there were no lights at Roland Garros, so this fourth set would end the match for the day. Given how well Federer had started, it appeared such a suspension and resumption on Saturday was more likely to hurt him than Djokovic. But Federer took a 0-40 lead and eventually broke serve, keeping the set alive. The crowd erupted with cheers usually heard during Davis Cup matches.

Naturally, it came down to a tiebreaker. Up a mini-break at 4-3, Federer fired two strong serves to earn triple match point. On his third, at 6-5, Federer whistled an ace down the T, ending the match at 9:37 p.m., in near darkness.

An enduring image following the last point: Federer raising his index finger in the air. Still number one? Or just this one moment?

"I would think it is the best match I played this year," Federer said. "I did really well, a top start when I was able to break. But I know he has always got something in his racquet to break me as well.

“There was a lot of pressure on Novak, but he handled it great. It was a pleasure playing against him. He can still achieve so much more this year."

What happened proved a sparkling reminder that Federer is—as is sometimes forgotten—one of the finest clay-court players in tennis history.

“It was best five months of my life, my tennis career,” Djokovic said. “I cannot complain. It was definitely an incredible period. It had to end somewhere. I knew it was coming. Unfortunately, it came in the bad moment. It was a big match today. But look, you know, it’s sport. I will keep on working hard.”

Though Federer went on to lose the final to Nadal, he’d at least gained the satisfaction of stemming the tide versus Djokovic—if only briefly. Djokovic that year went on to win Wimbledon and the US Open, the latter run highlighted by him yet again overcoming two match points to beat Federer in the semis. Since that day, Djokovic’s record versus Federer at the majors is 8-1, his only loss coming in the semifinals of Wimbledon in 2012.

Their 2011 Roland Garros encounter will be remembered less as a classic and more as a cult match: a glittering, self-contained gem between a superstar on the ascent and a longstanding maestro who on his most challenging surface once again displayed his ageless genius.