Tunisian voters appear to have up-ended their nation’s politics in Sunday’s presidential election, rejecting established leaders for two outsiders with 39% of votes counted.

Kais Saied, a conservative law professor, and Nabil Karoui, a media magnate held in detention since August, have an apparently solid lead over a moderate Islamist candidate and seem set to advance to a run-off vote in October.

Eight years after Tunisians staged the first of the Arab Spring revolutions to overthrow autocratic rule, Sunday’s vote represents a sharp rebuke of democratically elected governments that struggled to improve living standards or end graft.

“He will fight corruption and establish a just state and continue the process of the revolution,” said fishmonger and Saied voter Noureddine el-Arabi, proudly showing the inky forefinger that proved he had voted.

Karoui has for years used his Nessma television station and the charity he founded after his son died to present himself as a champion of the poor and a scourge of government, while his critics describe him as an ambitious, unscrupulous, populist.

He denies all claims of wrongdoing against him, including old tax evasion and money laundering charges which kept him in jail on election day, calling them an undemocratic plot.

“We hope that Karoui will keep his promises and keep helping us like he did in recent years (with his charity),” said a woman at Tunis fish market, who did not want to be named.

His wealth and massive electoral organisation stand in sharp contrast to Saied, who spent so little on his campaign that Tunisians joke it cost no more than a coffee and packet of cigarettes.

Saied, who speaks in public in formal Arabic as if in a faculty meeting, drives an old car and wants to remain in his humble house if elected rather than move into the luxurious presidential palace at Carthage.

A social conservative who backs restoring the death penalty and rejects equal inheritance for men and women, Saied’s main focus is decentralisation in a country where politicians in the capital have traditionally dominated. With 39% of votes counted, Saied was on 19%, Karoui was in second place with 15% and the moderate Islamist Ennahda party candidate Abdelfattah Mourou was on 13%, the official figures showed, proportions that now appear to be holding.