LA PAZ – Bolivia’s presidential election is set for a historic runoff as Sunday’s vote concluded, disrupting over two decades of rule by the dominant party in the Andean nation.

A centrist, Sen. Rodrigo Paz, drew more votes than the front-runners, although not enough to secure an outright victory, early results showed.

Former mayor Paz, who has aimed to moderate the opposition’s calls for austerity as a remedy for Bolivia’s looming economic challenges, will compete against ex-President Jorge “Tuto” Quiroga, the second-place finisher. Bolivia will hold its first runoff since returning to democracy in 1982 on October 19.

“This economic model must change,” Paz declared to crowds who cheered and chanted, “Renewal!”

Paz’s campaign garnered unexpected momentum by partnering with Edman Lara, an ex-police captain known for his social media presence and evangelical support, appealing to voters seeking a stance against corruption within the security forces.

With over 91% of votes tallied by Sunday, Paz received 32.8% of the vote, while Quiroga gathered 26.4%. A candidate needed over 50%, or 40% with a 10-point lead, to avoid triggering a runoff.

Quiroga congratulated Paz on his lead.

“What happened is unprecedented,” he said. “Bolivia told the world that we want to live in a free nation.”

An establishment confronts its demise

The election results were a setback for the Movement Toward Socialism (MAS) party, which has largely governed since charismatic former President Evo Morales came to power, part of the early 2000s “pink tide” in Latin America during the commodities surge.

The official MAS candidate, Eduardo del Castillo, ended in sixth place with 3.2% of the vote. Senate president Andrónico Rodríguez, viewed as the party’s most promising contender at 36, secured 8% of the vote.

During his almost 14 years in power, Morales expanded the rights of the country’s Indigenous majority, defended coca growers against U.S.-backed eradication programs and poured natural gas profits into social programs.

But the maverick leader’s increasingly high-handed attempts to prolong his presidency — along with allegations of sexual relations with underage girls — soured public opinion against him.

Discontent turned into outrage as Bolivia’s once-stable economy imploded under Morales’ protégé-turned-rival, President Luis Arce.

Annual inflation rate has soared from 2% less than two years ago to 25% as of last month. A scarcity of fuel has paralyzed the country. A shortage of U.S. dollars needed to pay for essential imports like wheat has crippled the economy.

As the crisis accelerated, MAS leaders traded blame. A power struggle between Morales and Arce fractured the bloc and handed the opposition its first real shot at victory in decades, even as its uncharismatic candidates failed to unite.

Morales’ supports heed calls to vote null

Blocked from running by a court ruling on term limits, Morales has been holed up in his stronghold of Chapare for months evading an arrest warrant for allegedly impregnating a 15-year-old girl while president.

He has branded Rodríguez a traitor for competing and encouraged his supporters to register their anger at his exclusion by casting null-and-void ballots.

His followers appeared to heed his call: An unusually high proportion of votes, 19%, were deemed invalid. Usually the share of blank and null votes doesn’t exceed 6%.

Voting even in the restive jungle largely passed peacefully, authorities said, with only minor disruptions.

A dynamite stick went off near the school where Rodríguez planned to cast his ballot in Chapare. When he arrived hours later, pro-Morales crowds assaulted him with bottles and rocks as he voted. Whisked away by guards, Rodríguez later called it a “difficult moment.”

A centrist takes a surprise lead

The win for Paz came as a shock to a nation that had been conditioned by weeks of opinion polls to expect that the leading contenders, Quiroga and businessman Samuel Doria Medina, would capture the top two spots.

Paz has sought to distance himself from pledges by Quiroga and Doria Medina to sell Bolivia’s abundant lithium reserves to foreign companies and turn to the International Monetary Fund for billions of dollars of loans.

But he has also launched blistering attacks on the MAS party and its economic model.

“I want to congratulate the people because this is a sign of change,” Paz said.

New face, old roots

Despite their grand promises, Doria Medina and Quiroga struggled to stir up voter excitement. Bolivians associate them both with the U.S.-backed neoliberal administrations that Morales repudiated when he stormed to office in 2006, declaring an end to Bolivia’s 20-year experiment with free-market capitalism.

“If they couldn’t govern well before, what makes us think they’ll do it now?” asked Yaitzel Poma, 30, as she celebrated in the capital of La Paz. “We have to learn from the past to make better choices.”

Bolivia faces a return to belt-tightening. After years of alignment with world powers like China and Russia, it seems set to reconcile with the United States.

Paz supporters have described the former mayor Bolivia’s southern town of Tarija as a fresh face with new ideas.

But Paz, too, has deep ties to Bolivia’s old political elite. The 57-year-old lawmaker is the son of former President Jaime Paz Zamora, who began his political career as a co-founder of the Revolutionary Left Movement, a party persecuted under the bloody military dictatorship of Hugo Banzer in the 1970s.

“What we’re doing is moving back in time,” said Kathryn Ledebur, director of the Andean Information Network, a Bolivian research group. “This is not a new actor with dynamic policies.”