Patrice Evra has revealed his agent thought it was a mistake for the Frenchman to join Manchester United after he was substituted after 45 minutes on his debut.
The left-back moved to the Theatre of Dreams from Monaco in 2006 but endured a nightmare experience in his first match for the club in the derby against Manchester City.
Speaking to Sky Sports, Evra disclosed he was ill before the game but he was too afraid to tell manager Sir Alex Ferguson about his condition.
And after being dragged from the field by Ferguson at half-time of the 3-1 loss, Evra said his management team had second thoughts about the transfer.
"When I played my first game with Manchester United, I ate some beans and pasta [before the game] and I feel really sick in my room," Evra said.
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"I was going to say to Sir Alex Ferguson, 'Look I'm not ready to play', but I was scared because they would say, 'He's not the man to play in the derby'.
"I play that game and get substituted after 45 minutes. I remember Ferguson was like, 'Now you sit, you watch and you learn English football'. It was a tough time.
"Even my agent said we made a big mistake to sign you for Manchester United. But I was really strong mentally to prove everyone was wrong for myself, because I'm really proud and I did it."
Evra went on to play 278 times for United over eight years, scoring seven goals and getting 33 assists on his way to winning the Champions League, five Premier League titles and three League Cups.
He eventually moved on to Juventus in 2014 - where he won two Serie A titles - before finishing his career with stints at Marseille and West Ham.
The France international also revealed he is in talks with United over a non-playing role at the club while he works at Old Trafford to gain his coaching qualifications.
"I’m doing my coaching badges with Manchester United, but I want to make it clear because people think I am already working for United,” Evra said on Sky Sports.
"There has been some talk but no, I am just doing my coaching badges. I know people are excited to see me back at the club.
"I’m having some important talks behind the scenes so we will decide if I will work for the club in a certain role or not. We will see."