The 28-year-old, who was born in the French city of Le Havre, began his career down the road at third-tier Cherbourg in 2011.
It would prove to be the first of many tests that would challenge Mendy’s determination and self-belief.
He joined the team as third-choice keeper but he took the chances offered to him as he slowly climbed up the pecking order.
“Every time he was called up to replace the number one, Edouard responded well on the pitch,” Ted Lavie, his former team-mate during the 2012-2013 season, tells BBC Sport Africa.
“He even joined the second team if needed. Myself and some other players fought to see him become the first choice.
“He was the best among our keepers and he was always involved, even as a bench guy.”
Unfortunately, Mendy’s third season with Cherbourg ended with the club being relegated. The only benefit was that he was offered a starting spot as the club played in the French fourth tier.
Things did not go to plan as the club were once again relegated – prompting the toughest period of Mendy’s life so far.
Empty promises and unemployment
At 22, his contract with Cherbourg had come to an end. He waited patiently for an agent to fulfil his promise to help Mendy move to an English League One club.
Mendy even rejected offers from lower-league clubs in France as he waited for a phone call.
It never came.
Instead, Mendy returned home to Le Havre without a job.
“He was trying to stay in shape: he jogged alone, went to the gym, trained with some local clubs. He never gave up,” Lavie recalls.
With no income at all, Mendy was forced to register with the Pole Emploi, France’s unemployment French agency, as he seriously considered his future in the game.
A change of fortune
After a year without a club, Mendy was running out of hope. But his life changed completely in 2015 thanks to his old friend Lavie.
The former France youth international, who has DR Congo heritage, even calls himself “the starter” – the man who got Mendy’s career up and running again.
“I was speaking with one of my friends, Dominique Bernatowicz, in charge of the goalkeepers at Marseille’s academy, and he was looking to fill a last spot,” Lavie says.
“I told him I used to play with one very good, tall, intelligent guy with a lot of room for progress. I added that he was trying to find any opportunity.”
Bernatowicz called the jobless goalkeeper. One chat was enough to convince him of Mendy’s motivation.
Mendy accepted the chance of a trial with the French giants, despite the fact it was only to become the fourth-choice goalkeeper. Even if he was accepted, he would only train with the first team – and play with the second team – sporadically.
“His trial was very good. He was raw but I quickly saw his qualities in his profile as he could stretch and dive easily,” recalls Bernatowicz, who described that week as ‘Mendy’s last chance’.
He convinced the club to offer Mendy a one-year amateur contract on minimum salary.
“Mendy was like a spare wheel, a filler,” Bernatowicz says. “For him, it was a challenge for eight or nine months where he just had to work hard.”
He used the opportunity to rebuild his career, while his pregnant girlfriend stayed back in Le Havre.
Mendy played just a handful of times for Marseille’s second team during that season. It was enough for him to be offered a two-year deal.
But would the keeper be satisfied with being a Marseille reserve? Other clubs were interested. Opportunities were coming Mendy’s way, thanks to an agent close to Bernatowicz.
“I didn’t decide for him – but I felt it would be useless to see him stay as a second or third keeper at Marseille,” he says.
Taking his chances
Among the offers were lower-tier clubs looking for a first-choice keeper. But Mendy decided to challenge himself again by joining Reims, then in Ligue 2, as a back-up.
He got the opportunity to prove himself sooner than he expected.
“During the first game of the season, the coach had to put him in as the number one received a red card,” former Reims midfielder Danilson da Cruz, a Cape Verde international, tells BBC Sport.
“And that day, he performed really, really well.
“Even as a number two, he always had the mindset of a leader and was very vocal in the locker room. He is valuable in a squad because he knows how to speak at the right time.
“He did his best to push the number one. When he was called up, he happened to be one of the best on the team.”
At the start of the 2017-18 season, Mendy was made first-choice keeper as David Guion replaced Michel der Zakarian as the manager of Reims, who were still in Ligue 2.
It was the opportunity that Mendy needed. That season he and his defence kept clean sheets in 19 out of 38 league matches. Reims gained promotion to Ligue 1.
In that first top-flight season, he played every game for Reims and managed another 14 shutouts. His performances led to a move to Ligue 1 rivals Rennes last year.
Two international debuts
His exploits in France have also helped Mendy achieve his dream of playing for Senegal, where his parents are from.
“When we were playing for Cherbourg with plenty of African players, we were always joking about results of each other’s national teams and country,” Lavie recalls.
“I remember even at that time he dreamed of playing at an Africa Cup of Nations with Senegal.”
But Mendy’s route to playing for Senegal was unconventional – as he actually made his international debut for Guinea-Bissau, where he also has family.
“During his first season at Reims, he was called-up by Guinea-Bissau but it wasn’t a Fifa fixture, so he went there knowing that he still had the option to join Senegal later,” Da Cruz says.
“I think when the coach of Senegal heard about that, he realised it wouldn’t be a good idea to lose him.”
Mendy earned his first Senegal cap in November 2018 and soon established himself as their first-choice keeper.
However, it has not been plain sailing at international level for Mendy either.
He was part of the Teranga Lions squad for the 2019 Nations Cup in Egypt and played in their opening two games before a hand injury ruled him out of the rest of the tournament, which saw Senegal reach the final.
For Mendy, it was another obstacle to overcome. His ability to recover from setbacks has helped him to a position where he can now look forward to playing in the Premier League and the Champions League.
“We recently joked about that [playing in the Champions League] because I have always said it would be with Barcelona, never Chelsea,” Da Cruz laughs.
“Nevertheless, by playing this top-level games, I am confident he will soon be among the best goalkeepers in Europe.”
BBC
