Reid: £3.5million purchase (CliveBrunskill/Allsport)

The 19-year-old Medina, a former team-mate of Wearsiders defender Julio Arca, has signed a contract that will keep him at the club until 2006.

Manager Peter Reid, who watched the striker in action for Argentinos Juniors earlier this year, said: 'I've seen Nicolas on a couple of occasions now and he's impressed me immensely.

'He has excellent passing ability, good tackling technique and has all the attributes of a complete midfield player.

'I am confident that Nicolas will settle at Sunderland you only need look at Julio Arca and the way he has adapted and taken to English football.

'He is an excellent addition to the squad and I'm confident he'll be a huge success.'

Medina made his debut for Juniors at the age of 17 and has been capped by his country at Under-17 and Under-19 levels.

The teenager said: 'I'm looking forward to playing at the Stadium of Light in front of big crowds, and I'm very happy to join Sunderland.

'I've spoken to Julio about the club and I've followed Sunderland on television this season.

'I know the English game is very fast and I can't wait to play in it. I'm very excited. I want to play the kind of football I play in Argentina at Sunderland.'

Reid was given a further boost last night when Arca declared himself fit for Sunderland's visit to Everton.

The Black Cats must win at Goodison Park and hope relegated Manchester City beat Chelsea at Maine Road if they are to finish sixth and qualify for Europe.

Reid said: 'Julio will be fit and it's great for us because he's a smashing little player. We go to Everton needing to win and that's what we'll be concentrating on.

'It's a game we're desperate to win and the players will be rested, up for it and looking to finish the season well.'

Sunderland are sweating on the fitness of Don Hutchison after the former Everton man missed training through illness.