In his long career of political stunts Nick Xenophon has never shied away from playing on his Greek heritage.

But there's one character from Greek mythology he'd rather not emulate — Icarus.

He was the boy who flew towards the heavens, became ecstatic with his ability to fly and forgot his father's warning that his wax wings would melt. His feathers came loose and he plunged to his death.

At Christmas time, Nick Xenophon was flying high.

A week earlier, Newspoll had confirmed his position as the most popular potential premier in the South Australia.

It was an early vindication of the one-time no-pokies MP's stunning gamble — to quit the salubrious surrounds of the Senate and lead a fledgling party into an election in his home state.

Late last year, the SA Best Party commanded an astonishing 32 per cent of the primary vote, according to the opinion poll.

Nick Xenophon had maintained a consistent mantra — his SA Best party was only interested in the balance of power in the South Australian parliament, not the power of the premiership or ministries.

Nick Xenophon has shared the election campaign spotlight with the Labor and Liberal leaders. ( ABC News: Dean Faulkner )

But SA Best kept announcing candidates, starting with a handful, then half a dozen, then 20, then a trickle more.

By the close of nominations, SA Best had 36 candidates running for the 47-seat House of Assembly.

On paper at least, that is enough to form a majority government.

As the party's ambitions grew, so did the expectations it faced.

Mr Xenophon got invited to leaders' debates and shared a stage with Jay Weatherill and Steven Marshall.

As the mathematical possibility of a Xenophon-led government grew, the media pack started agitating for some actual policies.

Never wanting to disappoint, Mr Xenophon and his team of hopefuls crafted some — quickly. Often on the eve of debates, sometimes on the morning of.

There was a feeling they were cobbled together, a bit like Icarus's wings — feathers of ideas plucked from various interest group manifestos — held together with wax and prone to melting under the spotlight of scrutiny.

'Just another Liberal'

While a small political machine struggled to deal with SA Best's new-found popularity, its competitors got stuck in.

Eager to protect Labor's vulnerable heartland, Mr Weatherill was quick to paint Mr Xenophon as "just another Liberal".

Equally keen to keep SA Best off Liberal turf, Steven Marshall repeatedly declared the former senator had stitched a deal with Mr Weatherill to keep Labor in office, but failing to offer a shred of evidence to back up the claim.

Nick Xenophon's traditional enemy, the pro-pokies lobby — happily helped his rivals, sending cash to the Liberals, Labor and the Conservatives.

The Hotels Association is also running its own campaign and the union movement joined the anti-Xenophon fray.

Then last week, Newspoll showed SA Best's stratospheric popularity had dropped back into the troposphere.

Its primary support was put at 21 per cent, but it may be closer to 27 per cent given the pollsters factored in that the party would not be contesting every seat.

One in three of the voters who had previously indicated Mr Xenophon was their preferred premier had now reconsidered.

Statewide polls might not be particularly helpful in understanding how many seats SA Best could seize from the major parties, because strength of support might vary wildly from electorate to electorate.

The party could still garner significant votes in some areas and claim seats of the majors.

But the most recent opinion polling was not a great sign.

Rivals take aim at Xenophon hopes

There were further concerns for SA Best when early voting began across South Australia this week.

The Greens and Conservatives treated SA Best like a rival, rather than a crossbench friend, encouraging voters to direct their preferences to both major parties ahead of SA Best.

Nick Xenophon will be hoping he doesn't need a travel agent any time soon. ( ABC News )

That could prove crucial in the race for seats — not least in Mr Xenophon's chosen battleground, the north-east suburbs electorate of Hartley, where he is trying to tip out a Liberal member.

Nick Xenophon's fears for his own political future should be shared by Mr Weatherill.

Labor needs SA Best to succeed, but only in Liberal seats, if it is to have a chance of securing a fifth consecutive term in office.

Mr Xenophon has joked during the campaign that he will buy a one-way ticket to Kabul if he fails to get into parliament.

It's too early to head to the travel agent, but if he does find himself jetting across the Khyber Pass any time soon, he might reflect on where his fall began.