The Black Cats have gained a reputation as a 'yo-yo team' in recent years, having twice suffered immediate relegation back to the Championship.

And the club is embroiled in a relegation scrap again, despite splashing out big cash on new players following their promotion.

West Ham boss Curbishley knows how hard the transition from Championship to Premier League can be, having twice done it with former club Charlton.

He told the East London and West Essex Guardian Series: "I'm sure Sunderland may have had higher expectations this year when you talk about the money they've spent, but I think any side that gets promoted has a big challenge," he said.

"You can either come in all guns blazing - which I think Sunderland did - stick with quite a bit of the squad you came up with and add to it, or don't do too much at all like Watford did on one occasion and bank it to make the club stronger.

"You have to make a big decision early on as to which way you're going to go."

Sunderland opted for the 'all guns blazing' approach as they laid out more than £40m on 13 new players in the summer and January transfer windows.

But Curbishley - who takes his side to the Stadium of Light tomorrow - believes that Roy Keane will have had a decent return from his men if they finish above the bottom three.

And he insists that, if they do achieve safety, they could make some progress next season.

He said: "I think they would look at survival this year as a success and they can build on that.

"They will become more attractive next year and the backing won't go away with the people involved. (So) it's vitally important they stay up this year."

Keane was the man to lead Sunderland to promotion in his first season in charge.

Although he has endured a tougher time of it this season, Curbishley believes it is all good for the Irishman's managerial grounding.

"I don't think Roy would have enjoyed being down the bottom with every game under pressure, but it's all part of his learning curve.

"He's had an unbelievable couple of seasons. Going up and if they stay up - that's success."