The Federer-Djokovic doubles combo a work in progress

Federer, Djokovic team up for the first time (1:24)

Roger Federer and Novak Djokovic play doubles together for the first time but fall in three sets at the 2018 Laver Cup. (1:24)

CHICAGO -- Roger Federer and Novak Djokovic playing doubles together for the first time was a resonant feel-good story Friday evening at the Laver Cup, but the more compelling narrative is how they lost to Kevin Anderson and Jack Sock.

The beaten icons raved about the experience afterward. They might end their storied careers winless as a doubles team but, as Djokovic said, "I'll carry this [experience] forever."

Federer walked off with a more practical benefit. On Saturday, he's playing singles against Australian Nick Kyrgios, who plays with a doubles player's mindset and many of his tools. Kyrgios' game is arrhythmic, based on striking first, fast and hard.

The doubles match demonstrated just how different the often overlooked art of doubles is from singles. Federer and Djokovic have 34 Grand Slam singles between them -- exactly 34 more than their opponents. Sure, Federer and Djokovic were a pickup team -- albeit a glamorous one -- but so were Sock and Anderson, who paired for the first time at this team event pitting Federer's Team Europe against Team World.

Federer and Djokovic were greeted like rock stars by about 20,000 fans when they took the court under ice-blue lights, with Team Europe having swept the day's three singles matches. Soon they looked like two green kids playing on a big stage for the first time. They sprinted across the court to meet and smack palms, pumping each other up. Strategizing in between points, Federer and Djokovic covered their mouths lest anyone lip-read. They stood with their heads nearly touching, whispering tactical nuggets. Would there also be an airborne chest bump?

The fun began in just the third game, when Djokovic unloaded a massive forehand that drilled his fellow icon right in the butt. The Serbian star looked horrified, while Federer appeared embarrassed. After a moment of stunned silence, many in the United Center crowd howled with laughter.

The outcome, for all practical purposes, was decided when Federer double-faulted to give the opposition a critical 5-4 lead in the match tiebreaker, opening the door for Team World's 6-7, 6-3, 10-6 triumph.

"It's like using different part of your brain," Federer said of doubles. "It's similar [to singles] but not the same. Like speaking a different language."

Doubles might be doomed to exist in the shadow of singles, but it isn't a mere filler on the tournament schedule or insurance if a singles player pulls out before a big match.

Sock has emerged as the best doubles player in the world, and Anderson has a handful of weapons. Sock and Mike Bryan won Wimbledon and the US Open, but Sock seems to find success with almost anyone.

"I don't play the most conventional doubles, that's for sure," Sock said. "I don't mind being up there, being active, trying to finish points, or I kind of stay back and hit a lot of forehands, which makes some guys uncomfortable. They don't see that sort of ball with RPMs and the spin. It's a little bit tougher to volley."

Djokovic put it this way: " At the net, Sock picks up everything around and reads play so well, it's a completely different approach [from singles]."

Federer said he found it difficult to develop any rhythm in doubles, because so many points end so quickly, with such a narrow window through which to push shots. "You have no rhythm for four or five games, then you have to hit a forehand close to the line even though you've hardly hit any shots like that so far."

It's odd hearing players as accomplished as Federer and Djokovic sound uncertain about doubles, like a pair of French chefs having to explain the nuances of vegan cuisine. Neither man is about to change his rich tennis diet from singles, nor is this lark likely to have any effect on their historic rivalry despite the "quality time" (Djokovic's words) and bonding they are experiencing at Laver Cup.

"I think rivalry will remain strong, as well," Federer said of Djokovic. "I want to beat Novak next time I play him, and I'm sure he will want to beat me."

When it comes to doubles, perhaps it's best to let sleeping icons lie.