The West Bank city of Ramallah, Fatah's political headquarters, went to sleep on Wednesday night to the sound of celebratory gunfire as the party's young supporters drove through the streets cheering exit polls which suggested victory.
By Thursday morning the euphoria had turned to shock as Palestinians tried to assess the effects of Hamas' victory.
What happens now, was the most frequently asked question in the most secular of Palestinian cities. Not many people had answers, but several joked about having a last alcoholic drink before it is banned by the Islamic movement that won four out of five seats in the city, formerly a Fatah stronghold.
Bassem Khoury, a Christian restaurant owner, said he feared Christians would be persecuted and that corruption among Fatah politicians would be replaced by corruption by Hamas.
"I can't see any problems with Hamas in the first year or six months. But once they get comfortable in their positions they may promote social change and my wife will be forced to wear headscarves and an abaya," said Khoury.
"If they declare that secular law has priority over Islamic law I will relax, but if they elevate Islamic law, I will pack my bags. It is not only Christians that are scared. Moderate Muslims who live a modern life are also fearful," he said.
According to Khoury, the son of a Hamas leader dined at his restaurant this week. He did not drink, but sat by racks of wine.
"He told me that we had nothing to worry about because Hamas would respect individual liberties, but I know that has not been the case in Gaza," said Khoury.
Nearby, Mahmoud Muhammad, 28, waited outside a mosque for the start of a Hamas victory parade. Unlike Fatah supporters, who celebrate with guns, Hamas supporters carried only their green flags.
"I am astonished by our victory. Things can only get better for the Palestinian people. I want Hamas to form a government and I don't want there to be any partnership with Fatah," he said.
"We have clean hands so all the money we receive will go directly to the people and not the pockets of the corrupt. Not everyone regards us as terrorists and we have our ways of raising money," he said.
Muhammad joined the crowds marching through Ramallah to the parliament building where Hamas now has a majority.
Supporters climbed the walls of the building and replaced Palestinian flags with the green flag of Hamas.
Two Fatah supporters then climbed the building and threw the flags into the crowd, who replied by throwing stones which hit them and smashed windows.
Police arrived as the Hamas supporters drifted away to mosques, answering the call to prayer.
A furious police chief ordered the Palestinian flag to be raised again and screamed over a loudspeaker: "No one takes down the Palestinian flag."
It was the first confrontation between Hamas and Fatah since the election but many fear it will not be the last.
Hishab Abu Ghosh, a member of the Democratic Front for the Liberation of Palestine, a leftist group which won four seats, said he was concerned about Hamas' ability to turn their emotional appeal into practical policies.
"Now they will have to deal with creating paradise on the earth not just in the heavens. They have no real political programme. What will they say to the World Bank? What will they say to the United Nations?" he said.