Cup kings Tranmere have defensive problems just as Newcastle and their deadly strike duo arrive in the FA Cup this Sunday.

Duncan Ferguson and Alan Shearer were good enough to score in a 3-0 win over Manchester United last weekend.

Since then Tranmere slipped alarmingly at Wolves as their league form continues to show a worrying case of cup distraction, with their only wins in 2000 in knockout competition.

"The 4-0 defeat at Wolves in midweek was just unacceptable," admitted boss John Aldridge.

"We have seemingly allowed our cup runs to upset our league form. It has happened to other clubs, now it's happened to us. There was a lack of pride.

"But we have worked them really hard this week, and I think you will see a different Tranmere against Newcastle."

The Worthington Cup finalists have defensive problems at the wrong time, with Clint Hill out injured for a couple of weeks.

But Steve Yates is back in the squad as boss John Aldridge faces difficult decisions before opting for the defence he believes can stop Ferguson and Shearer.

"They are on fire, there's no doubt about that. Last week they were turning over United, and now it's our turn to try to stop them," said Aldridge.

Should they lose, Newcastle would be the fifth Premiership side to fall at Prenton Park this season.

But the Tynesiders are the only top-flight club to have beaten Tranmere in the last two seasons, doing it in both domestic competitions last season.

"We obviously owe them one. We didn't do badly in either match but lost narrowly both times. Now we have the chance to get our own back," said Aldridge.

Irish under-21 midfielder Alan Mahon is Tranmere's main worry, and is considered only 50-50 to play.

Newcastle boss Bobby Robson could celebrate his new contract with a semi-final place on Sunday but warns against complacency.

"We can't talk about going to Wembley unless we beat Tranmere," he said.

"They know the importance of that. Everybody is focused on one match, not the second match or indeed the third match. We're three matches away from winning the FA Cup.

"If we think like that, we would be very unprofessional and we can't be like that. We'd have egg on our face and we mustn't do that. I won't let them."

Midfielder Rob Lee is suspended while Nolberto Solano is injured, and that could mean a start for Didier Domi.

Robson has had concerns over Ferguson, who strained his back in the 3-0 win over Manchester United last Saturday, but he is in the squad along with fellow doubt Nikos Dabizas

Georgian Temuri Ketsbaia has been suffering with tonsilitis and has not trained, but he could also still make the 16.