Former Scotland winger Pat Nevin feels Sunderland will have regrets after their FA Cup home defeat to Newcastle.
The visitors were comfortable 3-0 winners on Saturday.
Nevin told BBC Sport: "Sunderland have worked hard and I think they will be disappointed with the first half - they were a bit timid.
"But if you look at the differences in finances in these clubs, the result was always going to be a tough one for Sunderland."
Alexander Isak struck twice, with Daniel Ballard also putting through his own net.
