SUNDERLAND'S FA Cup heroics have come at a cost after learning that fans' favourite Julio Arca will be out of action for at least two weeks.

Arca was part of the Black Cats side who overcame Division One rivals Sheffield United yesterday to book a place in the semi-finals of the world famous competition.

But the Argentine winger suffered knee ligament damage in the second half of the tie and had to be replaced by Paul Thirlwell.

Manager Mick McCarthy is refusing to be downbeat and has challenged his fringe players to force their way into his plans for Wednesday's visit of Preston to the Stadium of Light.

McCarthy said: "Julio has tweaked his medial ligament and it will be a couple of weeks at least.

"But that will give someone an opportunity and he will have to come in and earn his corn, just has Julio has done."

Tommy Smith's superb strike proved to be the crucial winning goal against the Blades.

The hard-earned victory has seen Sunderland installed as 8/1 third favourites to win the trophy they last lifted 31 years ago on that memorable day at Wembley when they defeated the then mighty Leeds United. They will be hoping to draw either Tranmere or Millwall with the other teams being Manchester United and Arsenal.

But McCarthy is refusing to get carried away and he has called for his players to keep focused on their primary aim - promotion to the Premiership.

McCarthy: "I breathed a big sigh of relief when the whistle went. It was the FA Cup semi-final up for grabs so they are bound to get nervous.

"You could sense that everyone's nerves were getting to them.

"The crowd were fantastic but tension did creep in.

"But we are in training tomorrow and we have a game on Wednesday. I know it's terrible but that's the reality.

"I just have to keep doing my job and somewhere down the line I will look back and take stock. I'm not pouring cold water on it because we are in the semi-final of the cup and I don't want to.

"But there are still 15 games to go in the league and it will be nice in the summer to reflect if we have achieved something.

"I'm not trying to put a dampner on it. Winning the semi-final doesn't mean anything. Getting promoted is still what we are looking for.

"We have games now until the semi-final."

McCarthy has never been involved in an FA Cup semi-final as a player or manager since starting his career in the 1970s.

And the former Republic of Ireland boss paid tribute to coach Ian Evans for helping to get the best out of match-winner Smith.

"Tommy Smith has come in and improved considerably. Taff (Evans) works with him in the mornings and he should take the credit for that."

Meanwhile, United boss Neil Warnock, whose side are higher than the Black Cats in Division One, hopes McCarthy's men can now go one step further and reach the final, he joked: "It would be nice to see red and white get to the final and they have got a great chance if they get the right draw.

"I would like to see them win it now."

Read more about Sunderland here.