Inter Milan boss Jose Mourinho believes coming up against your old players can be a more difficult task than people realise.
The former Chelsea boss welcomes his old team, which still contains many of the players he managed, to the Giuseppe Meazza on Wednesday in the first leg of their UEFA Champions League last-16 tie.
With Inter leading the way in Serie A, some pundits have tipped Mourinho's inside knowledge of his opponents as a potential edge over the Premier League leaders.
However, the former Porto manager feels otherwise, suggesting it would be complacent of him to rest on his current knowledge of their team.
"I know Chelsea well but that doesn't mean it's easier, sometimes it's more difficult." Mourinho said.
"Sometimes it's more difficult because when you know so much about the team, if you don't decide what is the right information to give to the your new players about your old players, you can get into trouble.
"I played against Porto with Chelsea the next year after I left - 2004/2005 with Chelsea - it was my team, my players, I knew everything about them and it was not easy.
"We won one game, we lost another one, so it's not easy," he reiterated.
Mourinho was also quick to highlight how well his opposite number knows his own side, with Carlo Ancelotti having spent 14 years as a coach in Italian football.
"I think Carlo Ancelotti knows Inter very well, said Mourinho, who won the Champions League with Porto in 2004.
"He has worked all his life in Italian football and played against Inter a dozen times and is a local man, a man from Milan, from the same city.
"I think he knows everything about us, everything about our players, but I don't think it's an advantage at all."
With striker Didier Drogba in phenomenal form of late, Mourinho is wary of the attacking threat posed by the Blues and he insists they will be coming to Italy in search of a lead to take to Stamford Bridge.
"I don't remember seeing a game involving Chelsea and them going on the field to defend, or not to win, or to play for a 0-0," he said.
"Inter are the same. It's a game which could be 180 minutes, but it may even be 30 minutes more.
"The first game is important, but I think the second is even more important because that's the one which decides the tie.
"You leave the first game usually without knowing who is going to reach the quarter-finals and you leave the second game with the knowledge of who is going through and whose participation in the Champions League is ending."
Meanwhile, veteran keeper Francesco Toldo could start in goal for the hosts after regular first choice Julio Cesar was involved in a car crash on Sunday.
The Brazilian was fit enough to train on Tuesday, but with the seriousness of the nature of his injury, Mourinho may not risk his keeper's health.
"It's not certain," he said. "I don't know how he wakes up tomorrow (Wednesday), maybe he wakes with his eyes closed and he can't see the ball.
"After a car accident you never know. You can have a reaction 24 or 48 hours after."