England were 105 runs ahead for the loss of one second-innings wicket on Saturday, only to implode to one of their worst defeats in this country.
They lost their last nine wickets for 99 runs, including a match-changing spell of 3-0 in six balls.
Australia’s target of 205 seemed stiff on a difficult batting pitch, but Head, promoted to open, crashed a 69-ball century – the second-fastest in Ashes history.
England’s defeat is the first two-day Ashes Test since 1921. The 67.3 overs England batted across their two innings at Perth Stadium is their fewest in a Test defeat since 1904.
It also extended their winless this run in this country to 16 Tests, including 14 defeats. England have not won a match in Australia since 2011.
The next Test at the Gabba, beginning on 4 December, is a day-nighter. Australia have lost only one of their 14 day-night Tests and in Mitchell Starc, who took 10 wickets in Perth, have the best pink-ball bowler in the world.
Asked what his message to England fans would be, New Zealander McCullum replied: “Keep the faith.
“Sometimes we get beaten and it looks pretty ugly, but there are times when having that type of mentality allows us to still believe in our abilities when we step out to play.
“There are times we don’t get it right, but we have to believe in what we believe in because it gives us the best chance. Just because we are one down in the series doesn’t change what we believe in.
“We have to stay calm, stay together, and plot our way back into this series, as we have done before.”
