That’s a lot of greatness in one photo composite. (Afp/AFP/Getty Images)

In case you are wondering how long it’s been since you watched a men’s tennis match on TV, it’s because it’s been a long time.

And why haven’t you watched men’s tennis?

Well, you’re American and you prefer American stars. Okay, so name five top American men’s tennis pros right now.

I’ll wait.

All right, I’m not waiting any longer.

No American is ranked in the world’s top 10. At the moment, our five best made-in-the-USA male tennis pros are John Isner (14th), Taylor Fritz (28th), Reilly Opelka (42nd), Sam Querrey (46th) and, of course, Frances Tiafoe (45th). ***

Alas, this flagging interest in men’s tennis across Sports Nation obscures the fact that we are in the twilight of the most spectacular, most dominant, most enduring three-fella show in the game’s history.

Switzerland’s Roger Federer, 38; Spain’s Rafael Nadal, 33; Serbia’s Novak Djokovic, 32.

Remember the Three Tenors? Luciano Pavarotti, Plácido Domingo and the other guy, which was unfair to José Carreras. Similarly, casual observers might consider the Three Tenors of tennis to be Federer, Nadal and the other guy, which is unfair to Djokovic.

So today, at the start of the U.S. Open — of which these three gents have won 11 of the past 15 titles — we celebrate their sublime careers by spitting out some surreal numbers to you.

But first, I am is reminded of the simultaneous brilliance of Édouard Manet and Claude Monet. Between 1862 and 1881, Manet was named Billboard artist of the year seven times and Monet was Billboard artist of the year six times. Either would’ve won it at least 10 times if the other never picked up a paintbrush.

Likewise, in women’s tennis, the incomparable Williams sisters, Serena and Venus, have been roadblocks to each other. Serena has a record 23 Grand Slam titles, Venus has seven; of Venus’s nine losses in a Grand Slam final, seven of them are to Serena.

Which brings us back to men’s tennis — I promised you otherworldly numbers.

Federer has 20 Grand Slam titles, Nadal has 18 and Djokovic 16 — they are No. 1, 2 and 3 all-time.

Only four men have won at least four Grand Slam titles after the age of 30 — Rod Laver and these three guys.

Since Wimbledon in 2003, Federer, Nadal and Djokovic have won 54 of the 65 Grand Slam events. I am going to repeat that in capital letters for emphasis: FIFTY-FOUR OF SIXTY-FIVE.

In Grand Slam finals, Federer is 20-11, Nadal is 18-8 and Djokovic is 16-9. Of their combined 28 defeats in those title matches, 22 times one of them lost to one of the others.

I mean, if any of these three had chosen, say, telemarketing over tennis, who knows how many more Grand Slam titles the other two would have?

And in a sport that skews young, dinosaurs Djokovic, Nadal and Federer somehow are the three top-ranked players in the world this year.

Federer-Nadal-Djokovic have been masterful contemporaries, calling to memory other overlapping trios of exceptional skill in world history:

Socrates-Plato-Xenophon: Remarkably, one of these chaps was the dimwit of the group.

Da Vinci-Michelangelo-Raphael: No better time to be a starving artist than the Renaissance.

Christopher Columbus-Vasco da Gama-Ferdinand Magellan: Pre-GPS geniuses.

Jean-Paul Sartre-Albert Camus-Simone de Beauvoir: More deep thoughts than a Jack Handey retreat.

The Temptations-The Supremes-The Four Tops: Who wasn’t singing in Motown in the 1960s?

Coke-Orange Crush-Dr. Brown’s Black Cherry: I know sugary sodas are supposedly on the way out, but this is still the golden age of soft drinks.

Paul Newman-Al Pacino-Robert De Niro: This speaks to the De Niro era before “Meet the Fockers.”

Tide-Cheer-Gain: Don’t sleep on the old-school laundry detergents.

*** By the way, is Andy Roddick still playing?

Ask The Slouch

Q. Why would Andrew Luck walk away from tens of millions of dollars? (Claire Miller; Houston)

A. To get to the other side of the road.

Q. Since the Washington XFL team will be the Defenders, I’m trying to get everyone I know to refer to the local NFL team as the Offenders. Will you help me spread the word? (Dan Felsenheld; Arlington, Va.)

A. On the case.

Q. Can you explain the “inverted yield curve” in sports terms? (David Levine; Fort Lee, N.J.)

A. Sure. Most of my marriages — and all of my divorces — are based on the inverted yield curve.

Q. I am a Baltimore Orioles fan. Your thoughts? (Michael Canary; Rockville, Md.)

A. Regretfully, at this point you are beyond help.

Q. How long after President Trump buys Greenland until Roger Goodell tries to play an NFL game there? (Terry Golden; Vienna, Va.)

A. Pay the man, Shirley.

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