Broad bowled the best spell of his Test career in the afternoon session
Stuart Broad's astonishing spell will go down not merely as one of the most destructive spells in Ashes cricket, but surely also one of the most influential.
Single-handedly, he turned this Test - and the series - on its head and wrestled England into a position from which they now have a real opportunity to win the Ashes.
At lunch, Australia appeared to be comfortably placed on 61-0, with England rueing their luck in having failed to win an lbw appeal against Shane Watson when he had made four.
Every time the ball landed on the arid pitch, there was a puff of dust, but few deliveries had threatened the batsmen. Suddenly, everything changed.
Broad came on after the break, and immediately made the ball swing - not much, but just enough.
Rather than trying to bowl too fast and aggressively, as he appeared to have been instructed to do earlier in the series, he simply bowled an immaculate and patient line and length.
This is the future for Broad. He is tall and capable of bowling a good bouncer, but his height also gives him a tremendous advantage in pitching the ball up.
His role model should be Glenn McGrath - same height, same pace, same length.
Having trapped Watson lbw for 34, Broad claimed the vital wicket of Ricky Ponting, who edged a delivery into his stumps for eight.
Moments later, Mike Hussey was on his way, lbw in a classic left hander's manner, for a duck.
Michael Clarke drove casually to short extra cover where Jonathan Trott took a good catch and the cream of Australia's batting had been blown away in eight overs.
Graeme Swann also contributed with four wickets, but two of those were the result of poor decisions by Asad Rauf.
The verdict against Stuart Clark really was poor, but it rather summed up Australia's plight.
In England's reply, wickets continued to fall as they looked to build carefully on their 172-run advantage.
Ian Bell was brilliantly caught by Simon Katich at short-leg off Mitchell Johnson, who also dismissed Paul Collingwood after the Durham man played a particularly limp shot to a well directed short delivery.
Tension suddenly gripped England's supporters as Strauss and Jonathan Trott clung on for the final overs of the day, and England will be hoping to add another 150 runs on the third day.
If they manage to do that, they will be strong favourites to secure the win they need to regain the Ashes.