Sir Alex Ferguson admitted that Owen Hargreaves' shock return to the Manchester United first team had turned into a disaster.
The England international midfielder had not featured for more than two years due to knee problems and was hit by a hamstring injury just five minutes into his comeback against Wolves.
Ferguson commented:"We took a gamble with Owen Hargreaves. We thought by doing that it would give us a compact midfield with experience.
"But he only lasted five minutes. It was a disaster. He has hurt his hamstring, which is unbelievable."
Ferguson added of his depleted side's narrow 2-1 Old Trafford success:"We have done really well to get a result.
"You have to admire the perseverance of the team, because we have done it so many times.
"But it was a long struggle because we made so many changes."