Miguel Llera played under Di Matteo at MK Dons and revealed that the "friendly" Italian can get angry when he doesn't like what he sees.
A former player under Aston Villa manager Roberto di Matteo has told the Birmingham Mail that the manager will get angry with his players if they do not meet his requirements, but insisted that the Italian can turn the club around.
Villa appointment Di Matteo as the permanent replacement to Remi Garde at the start of the summer, and the task awaiting the former European Cup-winning Chelsea manager is arguably the greatest that has faced any Villa boss in nearly three decades.
The Birmingham club are facing the imminent start of their first season outside the top flight since 1987, and Di Matteo has been putting his players through their paces in pre-season.
One man who knows what it is like to play under the 46-year-old, albeit in his very early days as a head coach, is ex-Sheffield Wednesday defender Miguel Llera.
The Spaniard was one of Di Matteo's first signings in his first job as MK Dons manager in 2008, and he revealed that the mild-mannered Italian has a mean streak if he does not like what he sees from his squad.
Llera said, via the Birmingham Mail: "He was always involved in training and leading the session. He would get involved in the sessions and that would help a lot.
"He would demand everything from the player. He’s not the kind of manager who steps back from the training session. He is very friendly, but he is also a very strong character. He would get angry if we were not doing the right thing.
"Of course he can turn it around. He has plenty of qualities, he has the knowledge and experience. I don’t know the people that were working before at Aston Villa but he will bring a lot of stability to the club. He will make the right decisions and use common sense - it's not easy to find someone like that."
The appointment of Di Matteo has bred a great deal of optimism amongst Villa supporters, although the proof of course will be in the pudding as the club gear up for the start of their Championship campaign.
The Villans take on last season's play-off finalists Sheffield Wednesday at Hillsborough on Sunday in their opening game of the season.