Partial vote tallies showed Sadr and his Marching Towards Reform coalition with his allies the communists leading after Saturday's vote -- making him a key powerbroker in deciding the next government.

Across the sprawling Sadr City district -- named after Moqtada's father, assassinated spiritual leader Mohamed Sadeq Sadr -- streets are rutted after years of neglect and litter spills out of dustbins.

"Today we finally have hope," unemployed father-of-three Ghassan Matar told AFP. "People are tired, they have had enough."

Looking around at the lamentable state of the neighbourhood he insisted that residents just wanted the basics.

"Here we are poor and we ask for nothing more than public services. We have never had a full day of electricity."

While the surge by Sadr's alliance has blindsided many, this apolitical man in his forties said it hadn't taken him as surprise.

Protests have been held across Iraq by Shiite parties and communists since mid-2015, calling for an end to the corruption that has stymied Iraq for the 15 years since the US-led ouster of Saddam Hussein.

Sadr tapped into the public wrath to fuel a political comeback following years on the sidelines after his militia battled Washington's troops following the invasion.

"We have to fight (corruption) for our good and the good of Iraq," Matar said. "The protests bore fruit."

- 'We beat them 5-0' -

Shiite bastion Sadr City provided lots of fighters for the Hashed al-Shaabi (Popular Mobilisation Units) that helped Iraqi forces inflict defeat on the Islamic State group.

Now people were celebrating another win after the performance of the Marching Towards Reform alliance at the polls.

"We beat them 5-0," shouted a young man as he rode by on an rickshaw.

In the same street, Salah Jamal, 24, was cleaning the pavement in front of the clothing store where he works.

He was adamant that Sadr should now make sure that his coalition assumes the head of a new government -- by no means a certainty given the mind spinning machinations of Iraqi politics.

"If we want to change things then the prime minister needs to come from Marching Towards Reform," he said.

"We have tried all the others," Jamal insisted. "But we have had no results."

Nearby his friend Hussein Hamel, 23, said that people were banking on things to get better.

"Everything is in ruins here," he said. "We want someone who can reconstruct our neighbourhood, we want electricity, water, cleaning, to finish with these years of collapse."

As soon as the first election results were mentioned in this vast district people began flicking victory signs with their fingers.

But not everyone was getting carried away after so many false dawns for a country still mired in troubles.

"If Marching Towards Reform does not respond to our demands we will also go protest against them, just as we protested against corruption" said day labourer Haydar Jolani, 23.