The candidate running against Tayyip Erdogan in Turkey’s presidential elections this weekend got a boost on Thursday when a tiny party candidate unexpectedly withdrew, and a carefully monitored survey gave him a more than five-point lead.

Muharrem Ince’s resignation as one of four candidates in Sunday’s presidential election might change the last days of campaigning in what is considered as Erdogan’s toughest challenge in his two-decade reign.

Turkey’s main stock index jumped 6% after Ince made the shock announcement in front of his party’s headquarters in Ankara. Financial markets are on edge given Kemal Kilicdaroglu has pledged to reverse Erdogan’s unorthodox economic policies.

Turkey’s sovereign dollar bonds rallied with longer-dated issues rising as much as 2.5 cents in the dollar to change hands at over 82 cents – levels last seen more than a year ago.

The survey by pollster Konda put support for Erdogan on 43.7% and Kilicdaroglu on 49.3%, leaving him short of the majority needed to win in the first round and suggesting the election would go to a run-off between the two men on May 28.

The survey was carried out May 6-7, before Ince’s announcement. “The possibility of Kemal Kilicdaroglu winning has increased with Ince’s withdrawal. I would not be surprised if he got 51%,” said Bekir Agirdir, manager of Konda, speaking on news website T24 after the announcement.

The findings in the Konda poll were largely in line with some other surveys that put Kilicdaroglu ahead. He was named candidate of a six-party opposition alliance and also heads the Republican People’s Party (CHP), the banner under which Ince unsuccessfully ran for president in 2018.

Erdogan’s re-election bid has been complicated by a cost-of-living crisis, triggered by a lira slump and soaring inflation, and a devastating earthquake in February which killed more than 50,000 people in Turkey and left millions homeless.

Ince, who had 2.2% support in the Konda poll, said he had been the target of a smear campaign.

“I am withdrawing from the candidacy. I am doing this for my country,” he said, but he did not back another candidate and asked people to vote for his party in the parliamentary elections.

Erdogan said he was “saddened” by Ince’s withdrawal.