Alastair Cook conceded his England side had been outplayed in every department as they surrendered the Ashes to Australia before Christmas.
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The hosts completed a 150-run win in Perth on the final afternoon - despite a maiden Test century from Ben Stokes - to go 3-0 up in the five match series and claim the urn for the first time since they inflicted a whitewash on Andrew Flintoff's men four series ago.
Cook said: "We've been outskilled in all aspects. It's hard to say that as a player but that's the honest truth.
"We've got to keep looking at ourselves, keep doing what we can do which is work as hard as we can to turn things around."
Cook insisted his side had not been taken by surprise by Australia.
"We knew what a good side they were in England," he said. "Any side coming to Australia, you have to be at the top of your game to compete. We haven't been there.
"They've been ruthless - ruthless in never letting us back in any game when they got ahead of us.
"But there's a lot of talent in the dressing room. Everyone's hurting now, it's an incredibly tough place to be. That happens in sport - there's a winner and a loser and at the moment we're in the losing dressing room and it hurts.
"All we can do is work as hard as we can on our games and come out on Boxing Day and try and put in a better performance."
Stokes' 120 in 353 all out was at least a crumb of comfort to England.
Cook said: "It was a fantastic innings - full of character on a tough wicket with those cracks, it's always daunting to see them. He put them out of his head and I thought it was an outstanding hundred.
"You never know in sport. That partnership was just starting to build. But, as always, just when we've got a partnership going we haven't managed to continue."
Cook admitted he was bracing himself for an inevitable inquest into how England, who won the Ashes 3-0 on home soil in the summer, had surrendered them so tamely after the opening three Tests Down Under.
Cook told BBC Radio Five Live: "I'm sure they'll be a lot of inquests. There always are when you lose.
"It is a tough dressing room to be in. We haven't had enough people in form and we have been punished for it.
"They just outplayed us. We haven't managed to score enough runs and whenever they needed a partnership they got it.
"There is always a balance between risk and reward and our shot selection has let us down."
Looking ahead to the final two Tests in Melbourne and Sydney, Cook was reluctant to talk about any changes to the England side in the wake of the Ashes defeat.
He added: "We've got to go there and try to win the games.
"It is very early to say what we do with the side. There are always calls for change when you lose. We have the players to do it - it's about delivery."
Asked if England's senior players still had the necessary hunger for Ashes battle, Cook told Sky Sports News: "It is still there. Sport is pretty brutal if you don't get your skills right and we haven't got them right in these three games.
"The simple fact is we haven't delivered out in the middle and you have to give a lot of credit to Australia."
Cook admitted he was now facing the biggest challenge of his career and added: "We've got some good men around us and we are going to need them in the next few weeks."
Australia captain Michael Clarke said his side were receiving deserved rewards for their hard work.
"What an amazing performance, not just throughout this Test match but over the first three Test matches," he told Australia's Channel Nine. "I think the boys deserve all the credit in the world for the work they've put in over a long period of time.
"It's a fantastic feeling.
"We couldn't be happier. We've felt for a while we've had a lot of public support. We've copped a little bit of criticism through the media and at times have certainly deserved that. That's why I say credit to the players: the way they've stood tall has been outstanding."
Clarke admitted to a few nervous moments as Stokes repelled them in the morning.
"It was a tough night's sleep last night," he said. "No doubt we were nervous.
"I think Ben Stokes deserves a lot of credit for the way he played. To come out and make a tough hard-fought hundred he deserves a lot of credit.
"Our bowlers did a fantastic job.
"It certainly wasn't given to us easy but we expect that. We've known from day one that playing against England's always tough. They've got a lot of good players and we've seen that throughout this series."
Clarke vowed he and his players would push for another series whitewash in the final two games.
"Our goal is to get back to being number one team in the world," he said. "No doubt we'll celebrate hard tonight and enjoy it - we deserve that - but we've got two more Test matches. We'd love to win 5-0 in this series."
Paceman Mitchell Johnson has been instrumental in Australia's success and it was perhaps fitting that he removed James Anderson - his 23rd wicket of the series - to seal the Ashes for the hosts.
It is perhaps most significant given the left-armer was a figure of fun for England's fans in the 2010/11 series while his international career was called into question due to a foot injury last year.
"I came back from injury and I had a lot of doubters there. I knew I'd done a lot of hard work, I just had the opportunity and grabbed it with both hands," he said on Sky Sports.
"This team that we've got here, we've just performed so well as a unit, everyone's just done so well and we all deserve it.
"It means a lot. To finally win the Ashes for the first time after being a part for a couple that we've lost is very special.
"I want to just thank the crowds that we've had around Australia. Friends and family supporting us, that's been the big difference as well, just having all that support, so this is for everyone.
"It's an unbelievable feeling to win the Ashes. Three-nil up and an opportunity to go 5-0 - it's amazing."