The 49-year-old feels that the Red Devils would be 12-15 points better off with the Scot still in charge while claiming Jose Mourinho will build a dynasty at Stamford Bridge
The Scot left Old Trafford in 2013 after winning 38 trophies in 27 years at the club, and both David Moyes and Louis van Gaal have struggled to replicate the form needed to be that successful in their short tenures with the Red Devils.
And Mendes feels that if Ferguson were still in charge rather than Van Gaal, the 20-time English champions would be much better off in terms of their league position.
“[Ed Woodward] is the right guy to drive Manchester United to find a way to win important trophies,” he told BBC Sport.
“But at the same time, he has just one problem – it’s completely impossible to find someone like Sir Alex Ferguson because he’s a god, he’s a genius and to find a genius is very difficult.
“You have one in England – Jose Mourinho.
“Having Sir Alex Ferguson ensures at this moment you have 12 or 15 points more. He’s finished his career, but he’s someone that’s the difference.”
As well as representing a large number of the world’s top players, Mendes also acts as Mourinho’s agent, and he revealed that the former Real Madrid boss intends to remain at Stamford Bridge for at least the next decade and become a Ferguson-like figure.
“Jose will stay for sure. He will be the Sir Alex Ferguson of Chelsea Football Club.
“He loves the supporters, he loves the city and I think he will stay there for more than 10 years.”