ATHENS – Appearing out of nowhere, and without a seat in Parliament, 35-year-old Stefanos Kasselakis topped a first-round elections run to head the faltering SYRIZA and will face 38-year-old Effie Achtsioglou in a runoff.

The two were runaway choices over three other candidates: With 99 percent of votes counted Kasselakis, who spent much of his time in the United States, had 45 percent and the former front-runner Achtsioglou at 36.2 percent.

They were followed by those now out of running: Nikos Pappas, convicted over a TV licensing scheme third with 8.8 percent, former finance minister Euclid Tsakalotos at 8.7 percent and 77-year-old Stefanos Tzoumakas with 1.29 percent.

With the party – now also called the Progressive Alliance after being rebranded from the Radical Left – dismantled after being routed in June 25 elections by New Democracy, former leader and one-time premier Alexis Tsipras quit.

That has left the major opposition scrambling to pick up the remnants and try to coalesce its wildly divergent factions that include Communists, anarchists, terrorist sympathizers, far-left extremists, Stalinists, Trotskyites and ecologists.

Kasselakis rose on the back of a social media presence and slick campaigning, surprised Achtsioglou but had the backing of a firebrand former deputy minister, Pavlos Polakis, who endorsed him.

The top two finishers now will square off in a second round on Sept. 24 to pick the party’s new leader although if Kasselakis wins he won’t have a seat in Parliament and it’s unclear who would speak for him there. He wasn’t a candidate for seats in this year’s elections before popping up to run for leader.

“The first step has been taken so that the country will have a progressive government soon. The country needs it,” Kasselakis told reporters outside SYRIZA’s headquarters.

Achtsioglou thanked voters for participating in droves and said the second round polls “will be decisive” although she has a lot of ground to make up and hasn’t been able to party Kasselakis’ sudden image as a darling.

“It will determine whether the fight before us will be given in political terms or not. The fight on the real field, in the Parliament and in society … SYRIZA cannot march in the murky waters of easy solutions. We have a responsibility towards the Greek people to be honest,” she said.

Pappas, who wasn’t jailed after his conviction – that doesn’t bar a candidate from being in Parliament – said that, “Our party comes out stronger” from the election. “It is a proof that we need to proceed quickly in the transformation of our party into a left-wing, progressive, democratic party.”

Kasselakis was a CEO at a shipping company and had no political experience in the party before he suddenly appeared and dominated news involving SYRIZA and the elections, while Achtsioglou was a former labor minister.

Whoever wins will be at a disadvantage, having only 47 seats in the 300-member Parliament and New Democracy able to govern at will without any substantial opposition beyond rival lawmakers making complaints.