Steve Smith has walked the tightrope between next big thing and next man dropped this Ashes series.

But finally the talented 24-year-old, who started his international life as Australia’s next blond legspinner, took the most crucial step in his career so far, scoring an emphatic unbeaten maiden Test century at The Oval.

Australia declared in a dominant position at 9-492 from 128.5 overs on day two of the fifth Test, with Smith still standing on 138 not out.

The declaration gave England 25 overs to survive before stumps, and when bad light ended play a few overs early on an already rain-affected day, England were 0-32 with Alastair Cook (17no) and Joe Root (13no).

Australia hit the accelerator after tea, to pile on 95 runs from 11.5 overs, with Smith (16 fours, 2 sixes) sharing in valuable lower-order stands with debutant James Faulkner (23), Mitchell Starc (13) and Ryan Harris (33).

England’s stalling tactics returned, with those 11.5 overs taking 64 minutes to bowl.

Smith took some advice from captain Michael Clarke to heart about putting milestone nerves to one side, as he became just the seventh Australian to blast a six to bring up a breakthrough Test ton.

Sitting on 94, Smith didn’t appear to have a care in the world as he effortlessly launched Trott over his head for a towering straight six.

Smith yelled “you beauty” at the top of the lungs as he punched the ear and embraced batting partner Brad Haddin.

The Australian No.5 played brilliantly on his way to 138 not out, an innings he desperately needed to prove he belongs at this level.

For a player in just his 12th Test, Smith has endured an interesting ride.

He debuted as a 21-year-old against Pakistan in 2011 as a spinner.

But after he was dropped six months later, Smith spent two years in exile re-shaping himself as a specialist batsman before earning a recall as a back-up batsman for this year’s tour of India.

He went desperately close to scoring his maiden Test ton in Mohali, out for 92, but it was the start of something.

Although not selected in Australia’s original Ashes squad, Smith forced his way in with two hundreds on Australia A’s UK tour.

Then rushed up the queue to play in the first Test at Trent Bridge, Smith perhaps best summed up where he was at as a cricketer with his first innings 53.

Smith was magnificent up until the loose, immature slash outside off-stump that saw him throw his wicket away and cost Australia dearly in the final wash-up.

Since then that paradox between classy, potential future captain and flaky continued.

He scored 89 in the third Test at Old Trafford, but was lucky not to be out three times before he reached 20 and ultimately he again threw his wicket away with a hundred in sight.

That’s when Clarke sat down with him and advised him to focus on 150 instead of 100 when the pre-ton nerves started rising.

At Chester-le-Street, Smith had a shocker, with brain-explosions at crucial times, and was in some ways luck to survive to The Oval given the way Phil Hughes and Usman Khawaja had fallen by the wayside.

The first ball of his innings featured another foolish swish outside off that would have had the dressing room cringing.

But 198 balls later, his teammates were on their feet as one to acknowledge a magnificent achievement and a further endorsement – after Shane Watson’s drought-breaking 176 – of an Australian batting resurgence.

All of a sudden Australia have four batsmen in the series averaging over 40, with Smith alongside Clarke, Watson and Chris Rogers.