"We always used to talk about four Welsh clubs: Newport, Swansea, Cardiff and Wrexham, but Newport fell by the wayside some time ago," Toshack said.
"If the same thing happened to Wrexham it would be a huge blow for Wales.
"I'm confident they'll win, but the players have to realise just what's at stake, what the consequences would be for all of them.
"You just hope that they can go out and get the job done and I'm sure that they will."
Toshack was speaking in Wrexham as he announced the latest Welsh squad, a squad that includes Wrexham defender Steve Evans.