The pair has routinely locked horns during the six-week federal election campaign, with Mr Frydenberg claiming his opponent's mother-in-law said she would vote Liberal, and Dr Ryan branding her rival the "treasurer for NSW".
In a final quarrel on Saturday, the Victorian Liberal Party complained to the electoral commission alleging one of Dr Ryan's how-to-vote cards did not contain a Mandarin translation of a footnote authorisation.
Dr Ryan, a paediatric neurologist, has denied the claim, declaring all her campaign material is properly authorised in the correct languages.
The Chinese how-to-vote cards were nowhere to be seen at a Hawthorn East polling centre visited by AAP but supporters were locked in a tense debate about Mr Frydenberg's support for Victoria during the COVID-19 pandemic.
"All the vaccines went to NSW," a supporter of Dr Ryan said.
A Liberal backer replied: "How many doses have you had? It wasn't that big an issue."
Liberal supporters were buoyed by the number of young people taking Mr Frydenberg's how-to-vote cards, while a teal-clad campaigner said people taking election material from each camp had been split about 50/50.
Kooyong has been a Liberal seat since 1945 and counts former prime minister Robert Menzies and ex-opposition leader Andrew Peacock among its past MPs.
Mr Frydenberg won the inner-east Melbourne seat in 2010 but saw his margin dwindle to 5.7 per cent in 2019.
Polling has indicated the race will be tight and Mr Frydenberg admits he's in the fight of his political life.
If ousted, he would become the first sitting treasurer to lose his seat since Labor's Ted Theodore in 1931.
Hawthorn resident Stuart, a regular Liberal voter who requested not to have his surname published, said he had not been swayed to change his vote to the Climate 200-backed independent.
"People probably don't recognise the amount of energy and effort that's been put in to managing the economy, and Josh has done incredibly well," he said.
Richard, aged in his early 40s, voted for lawyer and Greens candidate Piers Mitchem and Dr Ryan second.
His reasons?
"Climate change, corruption and gender equality."
Labor candidate for Kooyong is medical physician and public health official, Peter Lynch.
While having views closely aligned to Dr Ryan, Colombian migrant Andrea, who has lived in Australia for 16 years, said her ballot was mostly about booting Mr Frydenberg.
"She's giving him a run for his money. It's a vote against him," she said.
"This government has been scary and horrifying and leaving people behind left right and centre."
Lily Jones, 22, and Seth Irvine both voted for Dr Ryan after doing some last-minute research on Friday, citing her progressive views.
"I knew who I didn't want to vote for," Ms Jones said.