Shortly after results showed a tight win for Erdogan, crowds of flag-waving supporters flocked to the Istanbul headquarters of his ruling Justice and Development Party (AKP) in the Sutluce neighbourhood of Istanbul.
People in cars held out flaming torches and honked horns while street vendors sold Erdogan scarves, flags and even 'Yes' CDs composed of campaign songs.
The victory margin was smaller than predicted by the authorities. In an interview with state television on Friday, Erdogan had predicted a far clearer victory saying polls showed a 55-60 percent share of the vote.
"To be honest, we did not expect such a result but never mind. It's still a good result," 25-year-old Derya said after joining the crowd on the street.
"We won, our people won. God willing we will have better future," she said.
"This is not a bittersweet joy. It is a nice joy. Let it be, we won!"
Nihat Kalaba, a member of the local AKP branch in Istanbul, also said he had expected a much higher win for Erdogan.
"But we are not very much surprised," he told AFP outside the AKP provincial branch in Sutluce.
"We expected an outcome of up to 58 percent but still we were cautious not to go too far," he said.
"What matters is the result. There's not much difference either one or two points higher or lower. We are happy."
'A stronger voice'
Erdogan had challenged European leaders in the referendum campaign.
"It was a tough campaign of course. Europe, America, Britain, France joined forces against Tayyip Erdogan, against Turkey," supporter Sezer Onen said. "We gave them a good lesson."
43-year-old Recep Kermen said Erdogan was a world leader.
"Our heart is beating with him. Let not only Turkey but the world know this."
But he said both the 'Yes' and 'No' voters "are our brothers."
The mood was similarly upbeat outside the headquarters of the AKP in Ankara.
A man who refused to give his name said: "Isn't it obvious? We came to celebrate. We expected more, but this means the undecided chose 'No'.'"
Yadigar Boztepe, a young woman holding a Turkish flag, said: "We expected more, but I'm happy."
Mustafa Umit Unsal highlighted the split in Turkish society which also extends to its European Union membership prospects.
"This result shows a part of Turkey doesn't want it to be strong and has a European mentality, the other part is real Anatolians."
He added: "We expect a stronger Turkey that has a stronger voice on the international scene.".
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)