Simon Mignolet has warned Sunderland it will take more than 90 minutes of concentration to get a result at Newcastle on Sunday.
Three times in the past month Papiss Cisse has scored injury-time winners for Alan Pardew's side, who needed a last-minute Shola Ameobi goal to salvage a point from last season's derby on Tyneside.
Mignolet, who saved a penalty in that game, said: "Exactly. They have scored a couple of goals in the last minute, we know that, so let's make sure we stay on our toes until the last whistle is blown."
Sunderland have gone eight games without a clean sheet, a run which contributed to Martin O'Neill's sacking and has left them outside the bottom three on goal difference only.
New boss Paolo Di Canio - beaten at Chelsea on his debut - now has six games to steer the club to safety.
Mignolet said: "Yes (it's surprise), if you see the individual qualities of every single player.
"Obviously, we didn't hope to be where we are now. With the qualities we have, we shouldn't be there.
"Let's hope we can now make sure we can get a clean sheet. That would be one part of the job done already, and then we will make sure we score a couple of goals."