A fervent supporter of President Recep Tayyip Erdogan, vegetable merchant Inal Kaya did not vote during the local elections in March and later regretted it when the ruling party lost in a shock upset.
"I was a bit fed up with all these elections," said Inal, peeling leeks at his stall in the district of Fatih, a conservative stronghold. It was the eighth election in just five years.
But on Sunday, he will have a second chance, thanks to a controversial re-run of the mayoral vote.
"And I will certainly be there," he said.
Every vote will count, since only 13,000 ballots separated Erdogan's chosen candidate, former prime minister Binali Yildirim, from the winner, Ekrem Imamoglu of the opposition Republican People's Party (CHP).
Many, like Inal, had assumed Yildirim's victory was guaranteed after a 25-year unbroken run of rule by the Islamic-rooted AKP or its predecessor in the city.
Others boycotted the vote to show their displeasure over the recent economic downturn, which has led to rocketing prices for basic goods and high levels of unemployment.
According to columnist Abdulkadir Selvi, close to the government, more than 400,000 AKP supporters did not come to the polls in March.
To mobilise them for this second attempt, the party is not taking any chances: "The upset voters are being phoned one by one for individual discussions," Selvi wrote.
Erdogan himself has sought to rekindle their fire, saying last weekend: "It's possible to be angry with certain people, but not with the cause."
- 'Resolving problems' -
Koksal Demir, a retiree from the working-class district of Kasimpasa where Erdogan himself grew up, recognises there are economic problems, but doesn't understand why AKP supporters are tempted to abandon the party.
Yildirim "is the only candidate capable of resolving the problems," he said from his small stool outside a cafe, keeping one eye on his game of backgammon.
Like most AKP supporters, Demir focuses on the improvement in living conditions since Erdogan came to power -- first as prime minister and later as president -- in 2003, pointing to the bridges, tunnels and hospitals built in that time.
That record is reflected in the AKP's campaign slogan: "We have done it, we will do it again."
But it has its work cut out ahead of Sunday's vote, with the opposition also going after absentee voters.
The AKP has tried to reach out to Kurdish voters, who number millions in the capital and could prove the kingmakers.
Many see electoral considerations behind the recent decision to allow lawyer visits to Abdullah Ocalan, imprisoned founder of the Kurdish insurgency, for the first time in eight years.
However, the largest pro-Kurdish party, the HDP, has thrown its support behind Imamoglu.
One advantage for the AKP is that it is unlikely to see a major swing away from the party among its supporters thanks to the fierce partisanship of Turkish politics, which is as much about identity as policy.
The controversy around the decision to re-run the election is unlikely to cause a major swing in votes because supporters only accept the narrative presented by their favoured party, said Emre Erdogan, professor at Bilgi University in Istanbul, who is not related to the president.
"The polarisation of the country is reflected in the way the public see facts," he said.
"While Imamoglu's supporters see the decision as unjust, those of Yildirim consider the first vote was stolen."
At his vegetable stall, Kaya certainly follows the pattern, condemning the "strange things" and "cheating" he says were done at voting stations.
"This Sunday, we will see the real results," he says.