Dimitar Berbatov said Gary Neville was Manchester United's best trainer, while Anderson regularly "p*****" him off during their training sessions.
The Bulgarian shared a dressing room with Neville and Anderson during an extremely successful four years at Old Trafford. Berbatov was part of the Sir Alex Ferguson squad which won two Premier League titles, the Champions League, two League Cups, and the Club World Cup between 2008 and 2012.
At the time, Neville was in the twilight years of his United career, while Anderson was a young up and coming prospect tipped for great things. However, Berbatov revealed the England defender and the former Porto midfielder were on completely different ends of the spectrum, when it came to training.
"Purely on training and wanting to produce every session and working hard, I must say Gary Neville," Berbatov said while speaking on behalf of Betfair. "He used to train really hard every single session.
"He had great professionalism and he always wanted to still show that he was better than the other players around him. Even at that age when I was there, he was still showing the young lads that he was better than them."
Can you think of any other players who used to frustrate their teammates in training? Let us know in the comments
Neville was a part of the infamous 'Class of 92' side which went on to be the foundations of some of United's most successful years. After coming through the United ranks, Neville went on to win 12 Premier League titles, two Champions Leagues, four FA Cups and three League Cups over the course of seventeen seasons at the Reds.
He hung up his boots after seventeen seasons in 2011, and went on to become one of the most recognisable pundits in football. Meanwhile, Anderson left plenty to be desired during his eight seasons at Old Trafford. The Reds beat several European giants to his signature in 2007, paying Portuguese giants Porto around £26million for his services.
But while Berbatov did allude to Anderson's evident natural talent, the Bulgarian ruthlessly admitted the United ace used to seriously frustrate him. "The worst trainer… I must say Anderson," Berbatov said while speaking on behalf of BetFred.
"Although he had a lot of quality and talent and was really good on his day, at training sessions, he really p****d me off sometimes. Like I maybe used to p*** some players off, Anderson used to p*** me off."
Anderson made 181 appearances for the Reds during an eight year stint between 2007 and 2015. However, he did not depart the Premier League with his reputation intact when he left the club to join Brazilian giants Internacional in 2015.
Former United defender Rafael once claimed the midfielder could have been the "best in the world" had he not enjoyed McDonalds so much. "We could be on the team coach and pass the services on the motorway and Anderson would jump up impulsively and yell 'McDonald's, McDonald's," Rafael said in his autobiography.
"Give him a football and he would just play with freedom and sometimes, if he got a good run of games, he could play as well as any player in the league. He picked up a lot of big injuries and then his problems with eating the way he did started to affect him.
"It was no coincidence that his best form came when he had a lot of games because that was when he couldn't eat so much. I will say something about Anderson - if he had been a professional football player, he could have been the best in the world."