In total, Dr Phelps won 23 of the 35 booths on Saturday, while Dave Sharma claimed victory in 12 booths.
“People were a bit dazzled by the big swings,” electoral analyst Ben Raue said. “The margins were comfortable enough that people felt they could call it.”
The booth results told the tale of Wentworth in three parts: the moneyed harbour-side suburbs, the beachside district, and the city-side suburbs.
Dr Phelps triumphed in the city and beachside districts, as booths which had backed Malcolm Turnbull in 2016 swung in her favour.
Mr Raue said the swings were biggest in the city area, with the Liberal vote dropping more in Paddington than anywhere else.
Across the three Paddington booths, voters turned on the Liberals in droves, with swings ranging between 26 and 30 per cent after preferences were distributed.
Meanwhile, the harbour-hugging moneyed suburbs around Vaucluse remained loyally Liberal but their support softened across every booth as some disgruntled voters clearly flaked away.
All 12 of the booths that Dave Sharma won were located in this blue-ribbon belt stretching from Darling Point and taking in Edgecliff, Double Bay, Bellevue Hill, Rose Bay, Dover Heights and Watsons Bay.
When Mr Turnbull was prime minister, the Darling Point booth – the local voting station for some of country’s most wealthy voters – was 81 per cent Liberal after preferences . On Saturday, this plummeted to 59 per cent.
The Australian Electoral Commission confirmed on Sunday that a “fresh scrutiny” of votes was underway, which led to adjustments to the Bondi Beach and Bellevue Hill booths, with analysts noticing anomalies in the preference distribution.
Dr Bonham said both booths recorded “astonishingly weak” preference flows to Dr Phelps compared with other booths of a similar size.
The Bellevue Hill result was eventually adjusted, with Phelps gaining nearly 300 votes on preferences, while Dr Phelps’ lead at the Bondi Beach booth widened by 679 votes after the preference count check.
At the Bondi Beach booth, which has a historically high Greens vote, around 80 per cent of the preferences were coming from Labor and the Greens, yet Dr Phelps received only 57 per cent of them.
“All of the [seven] Bondi booths, except for this problematic one, had preference flows between 78 to 81 per cent to Phelps,” Dr Bonham said.
Mr Raue said the corrections meant “it had become a lot harder for Mr Sharma to win”.
“He needs every postal vote to be returned and an very high proportion of those to win.”
Dr Bonham said the result was “still a bit dicey”.
“There could still well be more mistakes. They happen. It’s not over.
“The postals are the big thing that will drive the margin down because they are flowing very heavily to the Liberals. They need that to continue.”
Lisa Visentin is state political reporter. She has previously covered urban affairs, and worked in federal parliament.