"One thing for definite there will be shocks in the Cup at the weekend and there is no reason why it can't be Northwich," said Rush.
"They have done well so far and it is matter of taking your chances. The longer the game goes on if Sunderland haven't scored the supporters will get on their back. It is up to Northwich to silence the crowd.
"You need a bit of luck and Northwich may get that luck. I have been quite fortunate in the FA Cup. When I played for Chester we went to Newcastle in the third round and beat them 2-0.
"The most important thing is they go there and enjoy it and have no regrets."