It may have taken four days, but the Ashes series has finally come alive.

Comfortably second best for more than half the opening Test in Brisbane, England's failure to live up to expectation and their own standards sparked fears that this winter's contest would be nothing more than a cakewalk for an Australia side that began their mission to regain the urn in frighteningly impressive fashion.

You may not find many Australian fans prepared to admit entertaining sympathetic feelings for the old enemy - the country is hardly renowned for compassion in the sporting arena - but it is not too outlandish a claim to suggest a one-sided series would not be universally welcomed down under.

The true beauty of last year's Ashes - and the key factor in it transcending cricket boundaries - was the infinitesimal margins between the teams.

And, however large the gulf in quality during the first three days' play at the Gabba, England's much improved showing on the fourth not only cast the slightest shade of doubt on the outcome, but suggested that this has the potential to be another epic series.

Though an England defeat tomorrow remains by far the most likely result - five wickets down, they must bat out the final day if they are to salvage a seemingly impossible draw - spectators were kept enthralled by a sensational afternoon of cricket.

Whether it be the way Alastair Cook dealt with the threat of Shane Warne on his first meeting with the leg-spinner, the obduracy of Paul Collingwood in surviving a hellish start to his innings before flowering late on, or Kevin Pietersen's audacious sashays down the pitch to Glenn McGrath, there was no shortage of entertainment.

But the battle between Pietersen and Warne, great friends and Hampshire team-mates, topped them all in terms of excitement.

Never mind the fact England trailed by 557 runs when Pietersen came to the crease, with the prospect of a four-day defeat in the opening Test looming large.

No matter that Shane Warne had just claimed his second victim of the innings on his favourite ground. And as for his first-innings failure...

After a relatively subdued start when consolidation was key, Pietersen grew in authority to unleash his dazzling array of strokes all around the wicket.

Effortless clips through mid-wicket and deft paddles to fine leg were interspersed with the occasional booming cover drive, while one sweep in front of square thudded into the boundary boards with a force greater than anything seen in this game.

There were verbals aplenty - so much for the so-called cosiness between the sides, a criticism levelled at Australia following their defeat last year - many of which came after Warne had a caught-behind appeal turned down when Pietersen had made 44.

Pietersen was forced to protect himself with his bat at one stage when Warne hurled the ball back towards Adam Gilchrist, and a couple of streaky strokes late in the day merely served to heighten the tension.

Pietersen's 153-run alliance with Collingwood for the fourth wicket, noteworthy in that it proved England's spirit remains unshaken, also suggested there exists a chink in the Australian pysche.

How else could one interpret the sort of field that saw Warne bowling to three men on the boundary and a solitary close catcher when the lead was in excess of 400?

Could it be that the Australians - the self-styled purveyors of positive cricket - had allowed the odd doubt to creep into their minds?

If they were unconvinced before today, Australia now know England will not surrender the Ashes without a fight, which should make good viewing for all concerned.