Regrettably for the U.S. Davis Cup team, it wasn’t hard to pick today’s topic—Croatia’s stunning upset over an American squad that, on paper, would be a favorite to win the entire competition. But if the tie was a bummer for American fans, it was a grand and sweeping affirmation of why Davis Cup is such a great event.

And while the indifference of the U.S. sports audience to Davis Cup remains a hybrid of news story and self-fulfilling prophecy, the massacre in Carson featured this encouraging statistic: The three-day attendance of 18,760 was the largest crowd ever to watch a first-round match in the United States.

Apart from that, Mrs. Lincoln, how did you like the play?

I had interesting messages from some members of the TennisWorld Cabal, which I’ll post below. But let’s get back to why the DC is the ultimate tennis event. Begin with this: It’s unpredictable. As this weekend so dramatically showed, DC is like the Olympics in that you may as well throw away the form chart going in. For whatever reason, players who are second-round cannon fodder for the stars at Grand Slams have a way of morphing into superheroes for DC and the Olympics. The big difference, though, is that at the Olympics, this adds up to unsatisfying chaos—and a list of medalists that reads like names culled from some witness protection program.

It’s different in Davis Cup, though, because it’s a team sport—and that changes things at various levels. An Ivan Ljubicic upset of Andre Agassi—in and of itself—doesn’t really count for anything in Davis Cup (as opposed to the Olympics), unless the other Croatians also do their jobs. And the Davis Cup has a long-standing, rich tradition that institutionalizes chaos; players from small, underdog nations often rise to craft a triumph over a tennis superpower. Which is exactly what happened this weekend.

It’s worth pondering how all this comes about, because the better you understand the nature of DC the more apt you are to appreciate how it has created a state of parity that is deeply satisfying—like the parity in the NFL.

The advent of professionalism stimulated amazing, international growth in tennis (who, anywhere in the world, wouldn’t kill for the chance to earn three million bucks a year for playing a sport while jetting around and staying in great hotels?). As a result, the list of nations that can claim to have at least one potential superstar (think tiny Switzerland, with Roger Federer), along with a pool of serviceable world-class journeymen, capable of beating anyone on the right day in the right place and on the right surface, has swelled significantly.

Then, consider the role of doubles. I’ve never been a big doubles fan or advocate, but assigning doubles such a critical role (see the post from the Cabalist below) in Davis Cup has turned out to be a brilliant stroke. And if you want to see proof that doubles can indeed matter, and rise to the same level of intensity as singles, just attend a Davis Cup tie that’s even at one match apiece after Day One. The first thing a good DC captain learns is never, ever, underestimate the value of having a good doubles team. (The significance of doubles also helps level the playing field between large and small or rich and poor nations.)

One of the most novel Davis Cup protocols is the concept of reverse singles. It’s a radical format that few sports have bothered to emulate in either form or spirit. But imagine how one-dimensional DC would be if it featured a far more logical (and streamlined) three-match format of two singles and a doubles. The nuances created by the reverse singles concept are numerous. For one thing, it manages to create more matchups and increase intrigue without pricing the small nations out of the market, player-wise. Most important, though, the ITF made a terrific rule change a few years ago, hoping to increase the number of ties that would still be “live” (undecided) on Day Three. It wrote a rule stipulating that on the first day, each nation’s No. 1 was obliged to play the other nation’s No. 2.

This rule puts extra pressure on the No. 1s and promotes parity in a number of ways. It maximizes the chances of the weaker nation, it further ensures the relevance of doubles (it means a lot more if the score is tied at 1-1 after the opening day), and along the way it also sets up the majestic, tie-ending fifth “rubbers” between the respective No. 1s—such as we had in the Roddick-Ljubicic clash.

Lastly, the pageantry and color of Davis Cup is a great antidote to the reserve that characterizes tournament tennis, and in a way that is utterly natural and universally accepted. The DC vibe just evolved that way, much like the ambience that developed around certain bands, like the Grateful Dead, Phish, Jimmy Buffet. And the energy, power, and inspirational—or intimidating—capacities of the crowd amount to a tantalizing wild card on the field of play.

So there it is. Advocates of the Davis Cup aren’t mindless jingoists, or in thrall to tradition. Davis Cup is an ingenious organism that has really blossomed through the growth of the game.

As the Croatian captain Nikki Pilic put it after the tie in Carson, “I mean, in Davis Cup, believe me, everything is possible. Doesn’t matter if you are seeded or not. I mean, with inspiration and team spirit, playing for your own country, you can reach times 150% of your potential, of your normal potential.”