O'Connor voters have elected Liberal incumbent Rick Wilson for a third term, as the Coalition Government scores a shock-victory nationwide.
Polls had consistently shown Bill Shorten's Labor Party on course for victory, but Scott Morrison appears to have led the Coalition back into majority government.
Labor had targeted the WA seats of Hasluck, Swan and Pearce, but all three Liberal incumbents received a swing towards them.
The Coalition also benefited from a collapse in Labor's vote in Queensland, picking up a handful of seats.
In the wake of an unexpected loss, opposition leader Bill Shorten resigned his party's leadership, with Anthony Albanese the current front runner to take his place.
In O'Connor, Mr Wilson won 64 per cent of the two-party preferred vote on a primary vote of 41.83 per cent, with most polling places returned.
Labor's candidate Shelley Payne won 21.84 per cent of primary votes, an 0.92 per cent increase from the 2016 election.
The Nationals' candidate John Hassell suffered a swing against him of 5.78 per cent, finishing with just 12.55 per cent of primary votes.
Pauline Hanson's One Nation finished in fourth place with 8.37 per cent.
One Nation candidate Dean Smith was narrowly ahead of Greens candidate Nelson Blake Gilmour, who's vote dropped by 2.32 points to finish on 8.05.
Shades of blue in Labor stronghold
Labor suffered a swing against them in all four polling booths in Collie, although the party still won the most primary votes.
At Collie Senior High School, Mrs Payne received 44.79 per cent, a drop of 9.58 points from the 2016 election.
Labor had a double-digit drop at the Margaretta Wilson Senior Citizens Centre booth, finishing with 42.50 after a 10.83 per cent drop.
At North Collie Hall, the party received 50.65 per cent of primary votes. Although easily in first place, it was a drop of 7.22 per cent for Labor.
Pre-poll votes show a 7.07 per cent drop for Labor's Shelley Payne, who claimed 47.62 per cent.
Priority to deliver
Mr Wilson thanked the voters of O'Connor for electing him for a third time and thanked the more than 300 volunteers and helpers who assisted the Liberal Party in the seat on election day.
"It is an enormous honour and privilege to represent O'Connor in Canberra," he said.
Mr Wilson said he was pleased at the swing he received in Collie.
"There were some really strong swings in Collie because I think the Labor-voting coal miners in Collie are starting to wake up to the fact that they've been abandoned by the Labor party," he said.
Mr Wilson said a similar phenomenon occurred in Collie as in Queensland, where the Labor vote collapsed over climate change policy.
"Collie is a coal miner community and people work in the electricity generation sector," he said.
"The people of Collie are starting to get a bit concerned at some of the Labor party's rhetoric on climate change and closing down the coal centres.
"That was very good to see that we got an increased level of support from a very low base in Collie."
The incumbent gave credit to Prime Minister Scott Morrison for staying focused on the economy and leading the Coalition to victory.
Mr Wilson said projects funded in the lead up to the election would now be delivered.
"There was a chance that the Labor Party could have reversed those budget allocations," he said.
Mr Wilson said his Labor opponent's comments after the election had not been gracious, although he said the campaign itself was civil.
"One of the things that I give Bill Shorten credit for, was he was gracious in defeat. I didn't actually see that from Shelley Payne," he said.
"I think she ran a good campaign, probably the first time the Labor Party have actually campaigned with a bit of conviction in the electorate of O'Connor.
"She's perhaps gained a small swing to her, but I think once the postal and absentee votes have been counted, that will come back and it will be pretty much line-ball.
Payne happy to have held ground
Mrs Payne said she was proud to have run a positive campaign and to have been a voice for progressive voters in O'Connor.
The Labor candidate said the election was very disappointing for the party and blamed Queensland mining magnate Clive Palmer's multi-million dollar advertising spend.
"We bore the brunt of Clive Palmer's advertising blitz, which is a shame," she said.
"I think Labor is looking forward now and looking towards the next election."
Mrs Payne said Labor held its ground in O'Connor and improved its share of the vote in Albany and Kalgoorlie, despite a national swing against the party.
Mrs Payne also thanked her volunteers and said she would head back to the Esperance council and would spend some time with her family.
She would not confirm whether or not she would have another tilt at a higher office.
The Nationals flop in regional WA
Despite holding all of their seats, The Nationals failed to win a single seat in WA in either house of parliament.
Along with their poor showing in O'Connor, the party only won 10.47 per cent in Durack and a mere 1.36 per cent in Pearce.
The Nationals have not won a federal seat in WA since 2010.
O'Connor candidate John Hassell said he was personally disappointed at his showing in O'Connor, but was pleased the Coalition was reelected.
Mr Hassell said the result was positive for live exports, superannuation and the economy.
"We probably needed to come out with a fairly loud and strong policy platform," he said.
"I don't think people realise just how badly we're being done by.
"Unfortunately for O'Connor, we're just going to keep getting more of the same and that is because it is a very reliable seat for the Coalition."
Mr Hassell said he believes The Nationals have a federal future in WA, but would need to rethink their approach.
After two failed attempts at the seat, Mr Hassell said he felt "a bit bruised" and was not sure if he would attempt another stab at politics.