Sometimes in sport, a player does something so unpredictable and so wonderfully stirring that it barely matters which side you support; you just have to stand and applaud.

An Australian teenager named Ashton Agar did just that at Trent Bridge on the craziest of Test match days when history truly was in a hurry. Agar, 19, on his Test debut and in only his 11th first-class match, scored 98 swashbuckling runs in 101 balls batting at No.11, the highest Test score by a last man.

Never mind the fierce rivalry in the DNA of any match between England and Australia, there was not a cricket aficionado in England, let alone Down Under, who did not want Agar to complete a century. Sadly, he fell two runs short, but the achievement of the Aussie spinner has drawn a line in the sand of this already compelling Ashes series.

No nerves. No fear. No hint of fallibility as Agar shared a Test record 10th-wicket stand of 163 with Phil Hughes (81 not out). Most impressive was that, when Agar reached the crease, Australia were reeling at 117 for nine, having lost five wickets for eight runs in 32 balls. Facing humiliation.

True, it meant he had little to lose, but it was not just the runs he made that stunned England and everyone watching, it was the way that he made them.

The last time a sporting teenager burst on to the sporting scene with such devastating influence was perhaps the day Rafael Nadal won tennis' French Open on his first senior outing at Roland Garros.

In cricket? You perhaps have to go back to 1993 and Shane Warne's 'Ball of the Century', when the Australian spinner bowled Mike Gatting around his legs with his stupendous debut ball in an Ashes series.

"It's a dream come true. Forever, I've dreamt of playing Test cricket for Australia," said the 19-year-old, having carried his team into a first-innings lead of 65 before England closed day two of this summer's Ashes on 80 for two.

"For my debut to start the way it has, I'm over the moon."

For drama and blood-stirring action, the Ashes rarely lets you down. Remember, this series, in the opinion of some, was supposed to be a foregone conclusion. A 5-0 whitewash to England against a transient, un-heralded Australian side whose coach, Mickey Arthur, was sacked three weeks ago because of the side's enduring poor form.

Well, after 14 wickets on the first day, a clutch more on the second morning, the heroics of Agar and Hughes and some sustained pressure by Australia's seamers, England know they are in a dogfight.

With England on 80 for two, leading by 15 and with eight wickets remaining at close of play on day two, it would be a brave man now who would predict the outcome of this match or this series.

As for Agar, the forecasts were swift and generous. "This kid's a good 'un," said the former England captain Michael Vaughan. "Australia, you've got a cricketer."

Agar, watched in the Nottingham crowd by parents John and Sonia and brothers William and Wesley, played more like a Test No.5 than No.11 in an innings full of assured strokeplay and containing 12 fours and two 6s.

He thanked Darren Lehmann, the coach, and his batting partner Hughes for helping him produce his best at his first attempt on the biggest stage when his country needed it so badly. There were congratulations too, of course, from Agar's family, repaid so remarkably for their hastily arranged flight from Australia. "They were on a plane straightaway once they found the news out [that he had been picked to play]," said Agar. "To have them there today made that extra-special to me."

It was vindication, too, of his decision to knock football on the head. "Cricket was always my No.1," said Agar. "I did play a bit of junior footy, but everyone grew a lot quicker than me. I was just the little fat kid getting smashed around, so I thought I'd give that a break."

Following the heroics of Agar and Hughes with the bat, Australia then made two early breakthroughs with the ball as Mitchell Starc sent back Joe Root (5) and Jonathan Trott (duck) in successive balls in England's second innings.

However, captain Alastair Cook (37 not out) and Kevin Pietersen (35no) helped England recover to 80 for two at the close, a lead of 15.

James Anderson, whose five-wicket haul had seemingly left England in control yesterday morning, heaped praise on Cook and Pietersen for digging the side out of trouble. The paceman also paid tribute to Agar and Hughes for their "frustrating" efforts with the bat.

"Obviously, it's very frustrating when we've got them 117 for nine. We want to finish them off quickly but all credit to the two guys who stuck in there and gave us a hard time," Anderson said. "It was a couple of tricky periods for us. The last-wicket partnership and then losing the two early wickets, but the two guys at the end fought really hard to get us through the night."

Asked if it will be awkward to bat on the final day, he said: "I imagine so, but we've got to get to the last day first. We've got to bat really well tomorrow to try and get us into a position where we can put some pressure on them."