Manchester City's players had doubts about Fernandinho when he first arrived, admits former teammate Micah Richards.
The City captain is now regarded as the club's greatest Brazilian player.
Richards told Match of the Day: "The only thing was he came into a team already doing well. People like [James] Milner and [Nigel] De Jong and [Gareth] Barry started that.
"The team was getting better and he filled the gap. He has been consistent for about nine years.
"When he first came, he was sick in pre-season. The intensity, we all thought he was awful. If he can't keep up with the running. You can quote me on that, we were like 'what is this'?
"It took him two weeks to get back fit and he's the best defensive midfielder [in the Premier League] from then. I played with Yaya Toure and Patrick Vieira, he wasn't as talented as them but he was more efficient than them.
"You could rely on him every single game. He'd do the same, always give 100 per cent. He was a great leader too. Spoke perfect English. You see those little yellow cards when he fouls you then says sorry. He used to do that in training all the time."