BIRMINGHAM - Sir Alex Ferguson insists that 18.3 million pound ($29.8 million) goalkeeper David De Gea will become a Manchester United sensation despite the Spaniard's howler which allowed West Brom to creep back into Sunday's Premier League clash.

De Gea, signed from Atletico Madrid in the summer, was responsible for allowing Shane Long to mark his Albion debut with an equalizing goal after Wayne Rooney's opener at the Hawthorns before the champion clinched a 2-1 win.

De Gea let Long's timid shot pass under his arms and immediately generated comparisons with Massimo Taibi - United's error-prone former Italian goalkeeper - as well as raising further questions over whether he is capable of handling the pressure at Old Trafford.

However, Ferguson believes it will be the perfect character test to see if the 20-year-old can fill the void left by retired star Edwin van der Sar.

"I said welcome to English football to him at halftime. We lost a goal that David should have done better on. Maybe it was a lack of concentration," Ferguson said.

Ferguson also laid down a marker with the referees after Mike Jones failed to give De Gear sufficient protection.

"He took a bit of a battering in the second half and he should have been protected better by the referee, but he was not," Ferguson said.

"It was good experience for him and if my recollection serves me correctly, coming from European football is a learning process for a goalkeeper.

"Peter Schmeichel's first game was on a wet Wednesday night against Wimbledon and he had a difficult time.

"His following game was against Leeds when he let in a poor goal. He went on to be arguably one of the greatest goalkeepers in the club's history in my opinion.

"De Gea is only 20 and he is very much a work in progress."

Meanwhile, Ferguson faces a defensive injury crisis just one match into the new season after Rio Ferdinand and Nemanja Vidic limped out of Sunday's victory.

Ferguson confirmed England defender Ferdinand is likely to be out for six weeks with a hamstring problem, while Serbian centerback Vidic suffered a calf injury.

Ferdinand will almost certainly be out of England's Euro 2012 qualifiers against Bulgaria and Wales. But more crucially, the 32-year-old appears to be facing a fitness struggle to avoid being absent for the vital trip to face joint group leader Montenegro at the start of October.

Vidic is awaiting checks on a calf problem could keep him sidelined for two weeks and on top of that double blow, Ferguson also discovered on Sunday that Brazilian rightback Rafael da Silva will be out for 10 weeks with a dislocated shoulder.

Agence France-Presse