The goalkeeper was booed by certain Posh supporters after his error gifted Bournemouth a 90th minute equaliser on Friday but Ferguson still has faith in his number one.
"I'm not having fans booing players when they make mistakes. I fail to see what good will come of that," he told the Evening Telegraph.
"No-one makes mistakes on purpose and when mistakes are made we should all be offering support and encouragement.
"Joe is a grown man and he will deal with the situation. He has a great temperament and I have no doubts that he will be fine.
"It's happened to him before after all. I remember him getting some stick after we lost at home to Yeovil once and he came out and played really well at Tranmere in the next game."
Source: PA
Source: PA