Malcolm Turnbull's double dissolution election gamble, aimed at strengthening his own authority and seizing control of the Senate looked to have fallen short of expectations at the close of voting on Saturday.
The Prime Minister's centrepiece 10-year company tax cut plan, unveiled in the   May budget, allowed Mr Turnbull to pivot and run a campaign that focused heavily on the traditional Liberal strengths of economic management.
But the claimed long-term benefits of those changes appear to have been outweighed by Opposition Leader Bill Shorten's fierce campaign against the supposed privatisation of Medicare.
In addition, Mr Shorten's promise to scale back negative gearing and capital gains tax breaks, as well as spending more money on health and education, appeared to have struck a chord with middle Australia. 
However, soon after polls closed strategists from both sides were still predicting a narrow Coalition win as the most likely outcome.
Treasurer Scott Morrison was quick to point out on the ABC, soon after polls closed, that "first-term governments always have a swing against them".
"I have not detected any mood for change around the country."
The prospect of a very close result, in which the Coalition is reduced to a razor-thin majority, could see Mr Turnbull face severe internal pressure almost immediately, especially given internal Liberal Party friction over sweeping superannuation changes contained in the budget that hit high-income earners.
A same-sex marriage plebiscite, promised for this year, also threatens to embolden conservative MPs still bruised after the dumping of Tony Abbott last year.
For Mr Shorten, any loss could throw up a challenge for the leadership under the new party rules, but party strategists said that if the Opposition Leader gained about 10 seats net he would be in a commanding position to survive.
Australia has not dumped a first-term government in 85 years, but with a record number of voters flirting with third party independents no side was confident of the outcome early on Saturday night and a clutch of Senate and lower house crossbenchers could become king makers in the 45th Parliament.
Exit polling showed a contest on a knife's edge, with a Nine Network survey of voters leaving polling stations being too close to call, and a Sky News exit poll coming in at 50-50. Sky's polling also showed the main campaign issues registering strongly with voters. Labor supporters nominated health and Medicare as the top concern at 83 per cent, and 70 per cent of Coalition backers listed the budget and the economy.
A Galaxy exit poll put the Coalition primary vote at 43 per cent, Labor's at 36 per cent and 9 per cent each was allocated to the Greens and others, and Seven/ReachTel poll gave the Coalition a 51-49 two-party preferred lead.
The two leaders spent election day scrounging for every last vote, with Mr Turnbull and his wife Lucy voting in his electorate of Wentworth in the morning before giving the media pack the slip and heading out to the battleground western Sydney seats of Lindsay and Parramatta
In a sign that both sides regarded Lindsay as still in play, Mr Shorten also visited, in a bid to win back the linchpin seat before flying home to Melbourne and a function in his electorate of Maribyrnong at the Moonee Valley racecourse.
Heading into the poll, Labor required a 4.1 per cent uniform swing to win 19 seats and claim the 76 seats in the lower house needed to form majority government.
The Coalition held 90 seats in the 44th Parliament, though that figure was reduced to a notional 88 seats after electoral redistributions, while Labor had held 55, which rose to 57 after the boundary changes.
An average of a plethora of public polls conducted in the last week of the campaign showed Labor's support had peaked and a late drift towards the Coalition had begun, with a uniform swing away from Mr Turnbull's government of 2.9 per cent - enough to see the Coalition reduced to about 82 seats and Labor claim 64, with four on the crossbench.
However, with voters indicating record levels of support for the Greens and other crossbenchers - in particular Nick Xenophon's NXT party in South Australia - strategists on all sides predicted significant seat-to-seat and state-to-state variations in the swing.
One senior Coalition strategist predicted Mr Turnbull would win between 80 to 82 seats, conceding that the trio of seats in NSW that became notionally Labor seats - Barton, Dobell and Paterson - would likely fall to the ALP, with perhaps half a dozen seats in play. In Victoria, the Liberals had pinned their hopes on the seat of Chisholm, which had been vacated by former Labor speaker Anna Burke.
Labor was also sweating on losing the Melbourne seat of Batman held by front bencher David Feeney - who Fairfax Media earlier revealed had forgotten to declare his negatively geared house - to the Greens.
"He will be lucky to survive tonight and if he does, in three years he is gone," a strategist said.
A well-placed Labor strategist predicted the Coalition would lose between eight and 12 seats and, in a best-case scenario, Labor would pick up the remaining few seats it needed to either scrape home or force a hung parliament.
Queensland Labor strategists suggested that a gain of three seats would be a good result for the ALP in the hours before polls closed, but their NSW counterparts were more bullish about the party's prospects south of the Tweed river, and suggested half a dozen seats could be won on the night.
"It feels like we are getting the base back," said one, but "not much more than that".
Western Australia also offered the potential for Labor gains, energised by the unpopularity of the Barnett government, with the new seat of Burt expected to land in the Labor column and the potential for Cowan and Hasluck to fall.
However, there were fears that the big swings may not translate into significant seat gains because of the big buffer enjoyed by the Liberal Party in the west in the 2013 anti-Gillard-Rudd landslide.
A huge question mark hung over South Australia, with both major parties nervous about the impact of the NXT party, which threatened to win the seat of   Mayo, held by dumped junior minister Jamie Briggs.
The fate of a number of other seats, including Barker, Grey, and even Sturt and Port Adelaide - held respectively by cabinet minister Christopher Pyne and Labor front bencher Mark Butler - were causing some nerves.
The final allocation of Senate preferences could take weeks to determine, with some predicting Mr Xenophon could win as many as four seats, Tasmanian firebrand Jacqui Lambie in line to win her seat and perhaps claim another, Queensland tipped to vote in Pauline Hanson and, in Victoria, Derryn Hinch was in line to be elected.