There isn't much Roger Federer doesn't know about tennis these days. But when it comes to the intricate strategies of big-time doubles matches, even the Swiss found he had a few things to learn.

With Switzerland playing France in its first Davis Cup final a year ago, team captain and Federer's co-coach Severin Luthi approached the top-ranked doubles team of Bob and Mike Bryan for some input into their upcoming doubles match against the French.

The twins offered to lend their coach, Australian David Macpherson, who then actually traveled with the Swiss team to Lille, France, to supply drills, video analysis and strategy guidance. Federer and Wawrinka posted a straight-sets victory over Julien Benneteau and Richard Gasquet, praising the insights of their impromptu doubles coach.

"One of the things I remember most from the whole tie is Roger saying to me, 'I had no idea how extreme the tactics are in doubles,'" Macpherson recalled, speaking to theSydney Morning Herald.

Federer, who won the Olympic gold medal in doubles with Wawrinka back in 2008, said, "I mean, I know there is obviously tactics in doubles, but I was just surprised at times against certain players that there are such unbelievable patterns to follow."

Not only did the last-minute hire help Switzerland win the tie against France, in the process it might just have revolutionized how Davis Cup teams approach the often pivotal doubles rubber.

Belgium has followed suit this year by bringing in recently retired Michael Llodra, a three-time doubles Grand Slam champion who has made 28 appearances for France in Davis Cup. He was recruited by Belgium's second-highest player, world No. 85 Steve Darcis for their tie against Britain this weekend.

"I'm very good friends with [Darcis] and we speak often," said Llodra at the ATP Paris Masters, recalling a frustrated phone call with Darcis following a Davis Cup defeat last year. "I told him so much, he said that it would be excellent for helping the team."

Llodra, once ranked as high as No. 21, never succeeded in lifting the Davis Cup for France. Assisting Darcis and Belgium in capturing the title would be a victory of sorts.

"I assure you I would not do it for all the teams. I did it because I'm friends with [Darcis] and David [Goffin], and it would be something if I could win this competition even as a sparring partner or consultant," Llodra said.

All this emphasis on doubles is hardly misplaced, and this year, it could be even more important than usual. With world No. 2 Andy Murray likely to win both his singles matches, the Belgians will look to defeat the second-highest British player—either No. 160 James Ward or No. 110 Kyle Edmund—twice, and will need to win the doubles rubber. But Britain, which could play Murray alongside his brother Jamie, a doubles specialist ranked No. 7, will still be heavily favorited.

Llodra will be supplying doubles tactics to a Belgian squad without a player ranked inside the doubles Top 100.

"In singles, it's instinctive, we know how to play tactically," 16th-ranked Goffin said. "In doubles, not necessarily. We do not know where to position ourselves, it's very different. To have someone come and tell us exactly what to do, where to stand, it clarifies things."

Britain will not be calling in any special reinforcements for doubles. They see themselves as having been at the forefront of doubles strategy all along. Ever since 2007, The Lawn Tennis Association (LTA) has had a specialized doubles coach, Canadian Louis Cayer, for its players and Davis Cup and Fed Cup teams. Cayer is scouting and training players from the moment their next opponents are known.

"The preparation begins the following day straight after the tie," Cayer told Tennis.com in an interview through the LTA. "This takes the form of gathering videos of our opponents, and analyzing statistical patterns.

"We speak to several players who have played them and gather their input on how to play them. It’s not a secret, but the key is in the preparation. We encourage players to go watch prospective opponents in person and we do additional videotaping. Then during the actual tie, we get a lot more into specifics... bringing practice players to simulate opponents and preparing our own patterns."

The Davis Cup final is set to begin Friday in Ghent, Belgium.