There was once a man who had the day of his dreams. The man was young, just 19, with willow boughs for limbs and piano player's hands. It was a summer's day at Trent Bridge, with traffic curling round the ground and the beery lads in July bloom but he batted on a Hawaiian beach at sundown, bare feet in the sea, unlit cigarette at his lips.

On Tuesday, Ashton Agar was a spinner for Australia A and Henley CC, on Wednesday he was a surprise debutant wheel-barrowed into a feeble line-up on the whim of a coach. Now he goes into the record books as the man with the highest ever Test score at No. 11 - 98 runs off 101 balls, 12 fours, two sixes - transforming a session, tipping over a match. And oh, what style! What languor!

Agar popped out to bat on his Test debut, as if on a half-remembered errand to buy a second-class stamp. Yet the pressure could not have been much greater. Australia had just lost five wickets for nine runs in 32 balls, the finest swing bowler in the world was reverse-swinging at 85mph and Graeme Swann, buttoned up from the wrists of his sleeves to the ankles of his trousers had been tempting, beguiling, flighting Australian batsmen into heavy-booted panic.

Waiting for Agar was Philip Hughes, tense, cussed, a man who had watched his batting partners come and go with barely the time to ask their names. Hughes was awkward, sensing the pressure of failure, the history, the deficit. The nine yellow pitches cut into the mint Trent Bridge grass lay indented like the deep wounds in the Australian batting line-up, still 98 runs behind. The groundsmen swept the pitch and repainted the crease. Agar waited calmly, patting, straightening, patting, the ground as the bowler turned on his heel and ran in. This was the beginning.

The sun in a pale blue sky sprayed with skeins of light cloud started to bake both the ground and the crowd. Agar drove Anderson straight down the ground for four. Then, four balls later, England appealed against him for a stumping off Swann. The third umpire took his time - it was close - and turned it down. But hey, what would it matter - this wouldn't take long.

Agar swept Swann for four, then flicked another boundary through point, with total relaxation. There was no tension in this man, composed without shadows. He pulled Steven Finn through midwicket, then fast and clean hit Swann straight for six. He had a lazy scratch. There was warm applause now. Hughes at the other end began to unwind joint by joint. The knitting done by Swann and Anderson started to unravel ball by ball. This was the middle.

Agar, it turned out, had good eyes, good hands, fast reflexes and an immaculate temperament. Quick between the wickets, long legs stretching forward to negate the spin, he could play both sides of the wicket. An extra-cover drive off Swann brought up the 50 partnership and for the spectators surprise turned to admiration to excitement. As he turned the ship around, they began to think, "I am here."

Had the Australian selectors missed a trick or were they anxious not to overawe a young debutant? Whichever, he'll likely never bat at No. 11 again. This was iron sweetness. It felt a little like watching Ben Hollioake on his international debut, also aged 19, at Lord's in 1997.

As Agar drew level and then overtook Hughes (who had been 21 when the ninth wicket fell), a bond seemed to grow between the two men. With Agar's fifty came a pat and with Hughes' a big hug . Agar brought the team scores level with an exquisite late cut for four. On the radio Glenn McGrath mused, "I thought that I was presenting a baggy green to a bowler."

Lunch was delayed and eaten hastily when it came. Everyone was back in their seats afterwards - what fool would miss the second act. In this most partisan of contests, there was excitement and appreciation for an Australian. An Australian! One who had spoilt the James Anderson show, and ruined Alastair Cook's bacon roll.

The 90s were slightly nervous, well, as nervous as Agar gets. He went past Tino Best's previous record score for a No 11. Of 95. On 98 he swung at Stuart Broad, but missed, then cut and missed. Cook and Broad conferred, the crowd grew impatient. Clap, clap, they went, clap clap, clap.

Agar couldn't resist. He swung again, made contact and Swann caught him, reaching, down on the boundary. The spectators were stranded between a huge cheer of relief and a terrible sigh of disappointment. Agar raised his old bat, scuffed at the bottom, bandaged at the side, and smiled. He wandered off. It was his third standing ovation. This was the end.

Outside the ground, in the Radcliffe Convenience Store and the Instrument Repair Centre life went on. For those watching this, it had changed, just fractionally, for the better. For Ashton Agar, it will never be the same again.