as expected, the only true doubles team won the tournament.
On the men's side all the top singles players know that if they ever played a best out of 5 sets doubles match against any of the top 30 doubles teams in the world they'd lose. They all know this, it ain't a secret. You have to practice doubles, it is a totally different game and the advantage of players playing together week after week is enormous.
Back when Davis Cup was best out of 5 sets, yes even when playing for your country, almost every time you'd see "two top singles players" playing against "two guys ya never heard off" the "guys you never heard of" always won.
Hell in NCAA tennis you have guys that don't even make the singles line-up playing just doubles. Why? Because doubles is a different game, yes, that's why.
The only exception to the rule is at the Olympics, and that is because at the Olympics you had "singles players" actually spend months playing together before the tournament began. And remember you have to play with your countrymen, so you had lots of "new teams" playing with one another. But even with that said, go look at the Olympic Men's Doubles Gold Medal winners in past 40 years, you'll see lots of doubles players winning the gold medal. And all those winners were playing against the best tennis players that ever lived (everybody plays doubles at the Olympics).