Although the Red Devils have not specified a fee, it is believed they have spent around £16m of the world record £80m banked from the sale of Cristiano Ronaldo.

And, while it is not expected Valencia will represent the end of Ferguson's spending, the United boss is already tipping the South American to make a big impact.

"Antonio is a player we have admired for some time now, having spent the last two years in the Premier League with Wigan," he said.

"I am sure his pace and ability will make a significant contribution to the team."

If nothing else, Valencia's arrival ensures Wayne Rooney should be given the more central berth he craves next season as the Ecuador star is unlikely to venture into the middle quite as much as Ronaldo.

As he has already gone through the Premier League settling-in period after spending two seasons with the Latics, there are no worries over whether Valencia can adapt either.

His lack of English may be a concern initially, although the main doubt of most United fans is a goalscoring return of just seven in 83 appearances for Wigan and four in 34 for his country.

Even though few would expect Valencia alone to match Ronaldo's phenomenal recent output, better will be expected from a player who spent a short time as a team-mate of former United star Diego Forlan at Villarreal.

Forlan's experience proves players of high quality can struggle to make an impact at Old Trafford, although Valencia is looking forward to the opportunity.

"Joining Manchester United is a dream come true for me," he said.

"I have enjoyed my time at Wigan but I am thrilled to have the chance to challenge for the biggest honours in club football here.

"Playing in front of 76,000 fans alongside players like Wayne Rooney, Rio Ferdinand and Ryan Giggs will be an amazing experience.

"I can't wait to get started."

The first Ecuadorian to play for United will get his first opportunity on a four-match tour of Asia next month, before the Red Devils head for a four-team tournament in Munich.

By the time Ferguson's side wrap up their pre-season programme against Valencia at Old Trafford on August 5 and head to Wembley for the Community Shield showdown with Chelsea, Valencia will have expected to be accustomed to his new surroundings.

Having turned down an approach from Real Madrid, Valencia is clearly keen to make an impact, although it is a measure of the vast sums of money that has been spent at the Bernabeu, what would normally constitute a significant signing - and is a club record for Wigan - is almost being greeted with a shrug of the shoulders.

"I hope the fans at Wigan can understand that I am an ambitious guy and a chance like this might never come again for me," said Valencia, who will be 24 next month.

"I am happy that the club has benefited from the move financially because I owe them such a lot. I have had a great time here."