Hammers full back Lars Jacobsen thinks the defence must look at themselves after the loss against Manchester United.

West Ham defender Lars Jacobsen has questioned the performance of the defence after Manchester United grabbed four second-half goals to snatch all three points at Upton Park on Saturday lunchtime.

The 31-year-old Denmark international could do little to stop the United onslaught, something that was a huge disappointment to the full back as West Ham gave up a 2-0 half-time lead.

“It’s not nice to concede four goals in 45 minutes, so as a defender, my colleagues and I have to ask ourselves what we could have done better,” said Jacobsen after the 4-2 defeat.

“Perhaps you could say that we defended too deep in the second half, because when you concede goals there are always reasons for it. They scored a free kick and in the first half we had a similar chance that Thomas Hitzlsperger just missed and I think that was the difference.”

Jacobsen did have some words to say about the controversial decision that saw Nemanja Vidic stay on the field after he seemed to be the last man when fouling Demba Ba.

“I was surprised that he wasn’t sent-off for the first Ba challenge, but obviously I’m not standing in line with the situation so I can’t see if he’s the last man, but if he is then it’s a 100 per cent red card,” said the Dane, who has now played 20 times in claret and blue.

“But we can’t blame it on that. We just put that away and look forward and say nothing about red cards or not – we shouldn’t have conceded four goals anyway, that’s what went wrong really.

“I thought we played a decent first half and were leading 2-0, but the free kick kicked it off for Manchester United and they put us under pressure at the end and scored four fantastic goals.”

Jacobsen may have blamed the West Ham defence for their capitulation, but he was still full of praise for the quality of hat-trick hero Wayne Rooney.

“I think Rooney’s second goal was a superb touch and a superb finish and sometimes you have to acknowledge that they have world class players and I think that’s why they scored four goals,” admitted Jacobsen, who is now looking forward to Saturday’s trip to the Reebok.

“I think it’s a real opportunity at Bolton,” he insisted. “We all know it’s a difficult place to play, but in the Premier League it’s always difficult and it’s a new chance for us.

“I think with the quality and the players we have available at the moment that it’s possible to go and get a good result there. That’s what we have to focus on at the moment and put the Manchester United game away.