Manchester United defender Wes Brown has warned his young team-mates they face a test of character against Barnsley at Oakwell on Tuesday night in the Carling Cup.

Manager Sir Alex Ferguson will ring the changes for this fourth round match with a Barclays Premier League fixture in mind on Saturday when they entertain Blackburn.

He will hand a debut to Gabriel Obertan, three months after the 20-year-old midfielder arrived from Bordeaux. Obertan has proved his fitness following a back injury in three games for the reserves.

Danny Welbeck - who scored the winner against Wolves in the last round - Darron Gibson, Federico Macheda and the Da Silva brothers Rafael and Fabio could all be involved.

Brown knows United will have to be fully focused if the Coca-Cola Championship side are to be despatched on their own ground.

He said: "When you play at Old Trafford it is never easy. However if you can get over the fear factor, the way we play, it can be very enjoyable.

"Then you go away to small ground, a tight area and it is a completely different game. They get stuck in, they are rattling and it can throw you.

"I think our young lads know what they are up against and those with experience will help. We certainly don't want any mishaps and I am sure we will be ready for the challenge."

Brown is expected to start after replacing Rio Ferdinand in the second half of the Champions League victory against CSKA Moscow in the Champions League in Russia in midweek.

He is ready to give a helping hand and believes the competition is a perfect launchpad for inexperienced players.

Brown said: "It is one of these trophies where the manager likes to put a few of the young players in.

"People used to complain about that but these youngsters are fantastic players and they need to start somewhere.

"This is one of the best competitions for them. The manager does not always do it, he throws in some experienced players as well. It is a good tournament to be and we definitely want to win it."

Barnsley are managed by former Old Trafford striker Mark Robins, who according to legend kept Ferguson in a job in 1990 when he scored the winner against Nottingham Forest in the FA Cup.

Brown added: "He was a great player for United and he is doing well now in his management career. I am sure our fans will pay him great respect."