The veteran racket stringer is helping Canada's cause at an historic World Group semifinal against Serbia in Belgrade that starts Friday. It's his job to make sure that stars like Milos Raonic and Daniel Nestor do not become high-strung during matches due to concerns about their primary piece of equipment.
"They get new rackets every day," said Gilbert, who owns and operates two Montreal tennis shops. "(A new racket) is like a fresh croissant."
Gilbert has strung rackets at about 35 Davis Cup events. He helped Canada reach the World Group semifinals for the first time with a victory over Italy in Vancouver earlier this year.
"It's a wonderful experience. I've been, travelling everywhere, a lot in South America in the Americas Zone quite often," said Gilbert, who sometimes works from 7 a.m. to 11 p.m. when he is with the Canadian squad.
"You get to know (the Canadian players and, also, you learn a lot about the equipment, because they're the ones that are creating the trends."
Gilbert, who is in his early 50s, started stringing rackets when he was a promising 15-year-old junior tennis player in Quebec. After he busted many strings while playing, his father made him take a course in the craft.
Upon completion of his junior career, he started working in a tennis shop and top players brought their rackets to him. One thing led to another and he started stringing for Davis Cup players.
He is also the official stringer for the Rogers Cup in Montreal, serving there out of loyalty in 2012 while bypassing a chance to work at the London Olympics. Gilbert, who has worked at the Montreal event for all but two years since 1980, recalled sneaking onto the court late at night to play impromptu hockey games.
"Former (tennis great Ivan) Lendl was the goalie, so that was a lot of fun," he recalled of a 1981 game.
Gilbert has also worked at the U.S. Open, landing employment after he made a cold call and offered his services. Early in his career when his financial resources were limited, he spent some nights sleeping in a small room full of stringing machines.
During the week of a Davis Cup event, he spends countless hours at the Canadian team's downtown hotel stringing rackets with a machine that criss-crosses strings on each racket before he cuts and ties each strand while carefully checking that the weight is just right and the sponsor's logo is stencilled on.
During matches, as witnessed during Davis Cup ties in Vancouver this year and in 2012, he often gets up from his seat below the umpire and darts underneath the stands to retrieve rackets from the dressing room while play continues.
"Stringing a racket is not that difficult," said Gilbert. "It's more a question of putting everything together, depending on the type of ball, the conditions, the level of humidity, the sun, the opponent. We have to adjust the tension according to the tennis court."
The Belgrade venue's hardcourt does not pose any extra challenges than those faced elsewhere. But Gilbert must still adjust each racket's tension according to the exact specifications of each player. He helps Raonic maintain his powerful serve and enables Daniel Nestor to achieve desired spin when playing close to the net.
"It's a privilege to be able to work with the top players," said Gilbert. "I studied economics at university. I never thought I would be using tennis like this."
As a youngster, he envisioned a career in international relationships. Now, he cherishes the relationships that he has developed with players from Canada and opponents from around the globe. He also appreciates the goodwill displayed in spite of the global bragging rights at stake.
"They're playing for their country, we want to win, but it's friendly," he said. "It's always: May the best win. I really like it."
Each year, Davis Cup competition begins with 130 countries and sees only 16 teams qualify for the World Group. This weekend's winner will advance to the final in November against the winner of the other semifinal between Argentina and Czech Republic.
According to Canadian Davis Cup team veteran Frank Dancevic of Niagara Falls, Ont., Gilbert has enabled Canada to excel on the world stage.
"I feel like he's the rock of the team," said Dancevic. "He's really a remarkable guy, and he has shown remarkable skills. I know it might sound a little odd, but stringing is extremely important to my game.
"I feel like he has just been so accurate (setting the tension) through the years and it's unbelievable. I feel like he's the best stringer in the world, really. … I haven't found a stringer yet who's been as accurate as him."
But Dancevic, whose memorable opening-night victory against Spain's Marcel Granollers helped Canada oust the world's No. 1 squad in January, said Gilbert provides much more than just technical expertise. The Canadians strive to be a close-knit group off the court in order to excel on it, and Gilbert plays an important bonding role even when not working with rackets.
"He's done so much for us, for the team, and not only as a stringer, but just as a friend and a guy there to support the team and to support us all," said Dancevic.
"He's been really good over the years. … It's a really good fit, it seems, for Canada."