England were simply superb as Australia crumbled in Melbourne.
The disparity between the sides was such that it was the most one-sided day's play in a Test I have ever seen, even including matches involving Bangladesh and Zimbabwe.
To bowl Australia out for 98 and then come out and bat like that was remarkable.
In theory it is possible to mess it up from here, but England are in an incredibly strong position. They will look to bat long, build a big lead and then their spinner Graeme Swann can come into play when Australia bat again.
The Australians will surely put up more of a fight second time around - they can hardly fail to - but England seem to be set to retain the Ashes.
It was a day that England captain Andrew Strauss could have not dreamed of while his opposite number Ricky Ponting would never have imagined such a nightmare.
For the tourists everything went right - starting with winning a toss that, while important, cannot be used as an excuse for Australia's collapse.
Anderson celebrates taking the wicket of Michael Clarke
There was only a little help but the England bowlers all got the maximum they could from the pitch. Chris Tremlett bowled with real intensity and aggression to follow on from his performance in Perth. He has a glare now and a presence and he is such an enormous man he must be horrible to face.
Tim Bresnan also enjoyed a good day and he is someone I would have brought in for the last Test. In the past the Yorkshire star has been used as a new ball bowler, which is the wrong role. He is a back-up bowler to come on as a change. Given that role, Bresnan delivered and even bowled the quickest ball England produced.
But special credit must go to James Anderson, who just goes from strength to strength.
There was a little bit in the wicket for the Lancashire paceman but it certainly was nothing like the helpful wickets he got against Pakistan in the summer. There was no movement through the air and in the past that might have taken away Anderson's threat but he is a different bowler now with many more strings to his bow.
He bowled accurately, with pace and he has the stamina to keep on performing - showing he is fully recovered from the slight strain he was carrying. He was simply outstanding and really is a formidable opponent.
The bowlers did their work and England will now look to build on Strauss and Alastair Cook's opening partnership, knowing that they are on the brink of retaining the Ashes.
As well as putting the tourists near to retaining the Ashes, what the performance also did was to put the pre-match talk of Australia's improved fast bowling and how England would fold in the face of sledging into perspective.
In Perth, Australia chiefly relied on Mitchell Johnson and Michael Hussey while Shane Watson again impressed. What we saw in Melbourne is that if those players do not perform Australia are liable fold.
Throughout the series they have been rescued by Hussey, who has come in with the team in trouble and scored runs. Today England accounted for him quickly and, without their knight on a white charger, the home side crumbled.
Of course, there should be some slight caution following Perth, where, after day one, I said England were close to retaining the Ashes only for them to lose heavily. But if Australia are to somehow win in Melbourne they will have to become the first Test side in more than 100 years to do so after scoring less than 130 when batting first.
England dominated but it should not be suggested that they got undue help. There was some grass on the track and these drop-in wickets can be a little damp, but the pitch certainly did not give England's bowlers much. Strauss's men bowled and batted with discipline while Australia had a nightmare that started with their selection.
It was understandable to go without a spinner at the Waca, but it made no sense to have an attack with five seamers in Melbourne. There was a little help for the bowlers, but the ball was not whooping around for either team.
Bresnan relished a changed role in the bowling line-up
Yes, the tourists had the better of the conditions as when they batted the sun came out, but the key difference was that they bowled with line and length. They induced 12 nicks in total, Watson being dropped twice, and that was just through bowling in the right areas.
When Australia bowled they could not find the same discipline, Johnson reverted to being the wayward bowler of earlier in the series and under pressure they started conceding boundaries.
All this came despite the momentum supposedly having shifted to Australia after they won in Perth to level the series. The papers had gone crazy with all the sledging nonsense, their quicks were meant to have found form yet long before the end the 84,345 fans were leaving in their droves. By the close, the MCG was less than half full as England brutally exposed the weaknesses in their team.
The hosts were rescued in Perth because Johnson blew England away, but with the Western Australian back to being a scattergun bowler there was little to trouble England's openers.
It all led to a day that people back in England will scarcely have believed possible. It was one of those magical days of Test cricket and happily it is all gone England's way.
I have always thought England have the better team, I have thought that all series. Perth was a blip, but I have always thought they had the team to retain the Ashes it was just a case of whether they would manage to. It now looks like they will.
Jonathan Agnew was speaking to BBC Sport's Jon Barbuti.
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