The ex-Molineux midfielder, who is now manager of Scottish Division Two leaders Cowdenbeath, has followed Berra’s progress since his move from Hearts in 2009.
“Christophe will be thinking that he (Johnson) is going to play so he’s going to have to play better than he’s ever played to stay in the team,” Cameron told the Sunday Mercury.
“I think it’s putting that pressure on yourself and the pressure from other players joining the club that helps you improve.
“It’s good to have that competition for places because it keeps you on your toes. It makes you realise that you can’t ease off for one minute – otherwise you will lose your place.
“By the looks of how he’s performing he’s taken that on board and Wolves are getting the best out of him at the moment.”