SIR Alex Ferguson is agonising over a £20m gamble on Brazilian golden boy Douglas Costa.

Ferguson has identified the Gremio midfielder as a man with the potential to provide the goals and creativity that United will be in desperate need of in the absence of Cristiano Ronaldo. But at such a hefty price tag, he knows Douglas represents a considerable risk.

Attempts to sign the 18-year-old on an initial three-week trial have been rejected by Gremio, who despite intimating they will only sell for £25m, are expected to deal at closer to £20m.

That is still an enormous fee for a teenager who has never played outside of his homeland.

Ferguson has more than £100m to spend this summer, following the £80m sale of Ronaldo and the £25m that was earmarked for Carlos Tevez. But he is not prepared to splash the cash unless he is certain he can find the players to take United back to the summit of European football.

And he knows he needs attacking players who can provide the goals and inspiration of Ronaldo and, to a lesser extent, Tevez.

Lyon's Karim Benzema and Atletico Madrid's Sergio Aguero remain in his sights, but the United manager refuses to be held to ransom - even after being handed the biggest transfer war chest of his Old Trafford reign.

Douglas would be another pricey recruit, but Ferguson must decide if he can afford to miss out on a player who has been likened to Ronaldinho in Brazil.

Even if he has a patchy record of signing South Americans, Ferguson has always been drawn to the flair of Brazilians and Argentines. But in all his time at United, he has seen numerous stars from that continent taken out of his reach by European rivals prepared to take a gamble on them as teenagers.

Gabriel Batistuta was a long-term target in the 1990s, but after his goal scoring feats in Italy with Fiorentina, United could never afford to lure the Argentine hitman to England.

Dithered

United dithered over Chilean striker Marcelo Salas in 98, when he would have been available for £10m - only to eventually see him become a major success at Lazio.

If there has been a weakness in Ferguson's transfer policy, it has been his failure to tap into the South American market at the highest level.

Ronaldo, Roberto Carlos, Rivaldo, Leonardo, Kaka, Robinho, Lionel Messi and Pato can be added to the list of players that United have missed out on down the years.

All too often Ferguson has been forced to enter the market once they've already proven themselves outside of their homeland, therefore seeing their valuations soar.

But the failure of those players that he did choose to take a risk on are sure to weigh heavily on his mind as he deliberates over parting with £20m for Douglas.

Uruguayan striker Diego Forlan and Brazilian World Cup winner Kleberson proved expensive mistakes, with both struggling to adapt to English football.

At the other end of the spectrum, Juan Sebastien Veron might have proved himself in Italy, but at a cost of £28.1m, the Argentine ranks amongst Ferguson's biggest transfer blunders.

Policy

There has clearly been a change in Ferguson's policy towards South Americans, with him hoping to build a base at United in the same way that Arsene Wenger managed with French players at Arsenal.

He was prepared to spend around £20m on Anderson as an unproven 19-year-old from Porto in 2007.

The Brazilian midfielder might have already made the successful switch been to Portugal, but he had only just recovered from a career-threatening broken leg.

Still Ferguson wasn't prepared to let a player, who scouts described as potentially one of the best in the world, fall to any of United's European rivals.

Likewise, United have plundered Brazil for teenage full-backs Rafael and Fabio da Silva, as well as Rodrigo Possebon.

Ferguson swooped after their impressive displays for Brazil's Under-17 World Cup-winning side and, in the case of the Da Silvas, beat Arsenal and Real Madrid to their signatures.

Another Brazilian teenager, Dodo, is expected to come to Old Trafford in a £5.5m deal from Corinthians, but Costa remains his priority after impressing with three goals in the South American Youth Championship in January.

BIRMINGHAM are to hand a trial to former United midfielder Quinton Fortune with Roy Keane at Ipswich also interested.

What is your verdict on Ferguson's transfer record down the years? Have your say.