© AP
But less than 10 minutes away by ferry, in the more secular neighbourhood of Besiktas, many voters passionately denounced Mr Erdogan.
The vote, for local elections that Mr Erdogan has depicted as a referendum on his rule, passed peacefully in both districts, but the gulf in views highlighted what many say is the mounting polarisation of Turkish society.
"The broader issue for me is how this is going to go on after this vote," said a senior international diplomat, referring to the bitter election campaign, which has featured allegations of corruption, a clampdown on social media and a vitriolic fight between Mr Erdogan and Fethullah Gulen, an ally-turned-enemy.
"When people say it is a fight to the finish, there is no finish line," the diplomat added. "Even if there is what many people would regard as victory [for Mr Erdogan's AK party] in the mid 40s [per cent], I don't see how you can call that a clear victory with a population as polarised as this."
Partial results late on Sunday night showed the AK party with more than 44 per cent support overall and ahead in the key contests in the cities of Istanbul and Ankara. But there were marked disparities between the two news agencies reporting the results from the polling stations - an unprecedented development.
While the state-controlled Anadolu Agency gave bigger leads to the AK party, the Cihan news agency, which is linked to Mr Gulen's movement, depicted narrower contests. Together with other Gulenist-affiliated media, Cihan also said it had come under large scale cyber-attack during the day, hitting its ability to process the figures.
The corruption allegations against those in Mr Erdogan's circle have rocked much of Turkey since high-profile raids in mid-December, but Sevim, an assistant in an Uskudar clothes store, is unmoved.
"I don't think these claims are real; I think they are intended to bring chaos. At the end of the day, everybody is corrupt," she said, arguing that the country is richer, freer and more peaceful than when Mr Erdogan came to power over a decade ago.
"We look at who is working for the country and the person who is governing us is really hardworking," she added.
It is a point of view echoed by many others in Uskudar who cast their vote for the AK party on Sunday.
"There was corruption in previous governments, but they are exposing this now because they want to put an obstacle in front of him," said Samet, a 24-year-old graphic designer as he leaned against the wall of a 16th century mosque and checked his smartphone. "All the same, he is gaining force, because whatever doesn't kill you makes you stronger."
Asked the likely result of the poll, in which the AK party has been seeking to maintain control of both Istanbul and Ankara, the capital, Samet's friend Gokhan simply said one name: "Tayyip Erdogan."
But at a polling station in Besiktas, on Istanbul's European coastline, there was much less consensus.
"We knew about the corruption, but now it is proven," said Yagmur, a medical student in her 20s, referring to a now-stalled corruption probe and recordings released on Twitter and YouTube. The government portrays both the investigation and the leaks as a plot by Mr Gulen's movement, which denies such allegations.
Yagmur has little doubt why the government banned access to both social media sites. "There has been even more corruption, that is why Twitter and YouTube are banned," she said.
Deniz, Yagmur's sister and also a medical student, expressed her hope that the elections will begin the process of dislodging Mr Erdogan.
"Some people forgot that they are elected by the people; instead they think it is their country," she said. "People want to vote to say no to this."
Reader Comments
to our Newsletter