By Yuri Kulikov and Natalya Zinets
KIEV (Reuters) - Ukrainian opposition leader Viktor Yanukovich won presidential elections Sunday, according to exit polls, but rival Yulia Tymoshenko refused to concede, in remarks which could presage a court challenge.
Yanukovich, 59, a beefy ex-mechanic who wants better ties with Moscow, staged a remarkable comeback from a former election disgrace to lead Sunday's runoff vote with 49.8 percent, according to pollsters ICTV.
Former gas tycoon and serving premier Tymoshenko, 49, who led crowds onto the streets in 2004 to strip Yanukovich of victory after a fraudulent election, trailed with 45.2 percent.
Legal challenges and street protests from Tymoshenko could further delay Ukraine's chances of repaying over $100 billion (64 billion pounds) of foreign debt and nursing its sickly economy back to health after a 15 percent collapse last year.
Two further exit polls pointed to Yanukovich winning but a stern-looking Tymoshenko was in no mood to give up and said that her team was conducting a "parallel count."
"It is too early to draw conclusions," Tymoshenko told a news conference. "Everything will depend on how our team defends the results. I ask everyone to fight for every result, every document, every vote, because a vote can decide our fate."
The exit poll results were greeted with applause at Yanukovich's campaign headquarters. "This means absolute victory for Viktor Yanukovich," aide Anna German told Reuters. "That leaves Tymoshenko with no chance."
The polls came after voting ended in snowy, sub-zero temperatures in this country of 46 million. Official results were expected during Sunday night.
Sunday's vote appeared to reflect a widespread feeling among Ukrainians that the Orange Revolution, which Tymoshenko co-led, failed to deliver prosperity or stability and instead led to constant political squabbling and deep economic crisis.
President Viktor Yushchenko, the other leader of the Orange Revolution, was eliminated from voting in the first round of the election after coming a humiliating fifth. He lauched a series of bitter personal attacks on his former ally Tymoshenko.
Voters were unenthusiastic about either candidate but seemed to feel Yanukovich, a former premier who stressed the fight against poverty, had the best chance of restoring order.
"We lost five years of our lives thanks to Yushchenko and Tymoshenko," said Oleg Nochvyn, a miner in his 50s in the eastern region of Donetsk.
"For five years they were promising us -- tomorrow will be better. Well, I get up the next day and it's worse than the day before ... Under Viktor Fyodorovich (Yanukovich) we had everything -- economic growth, everything was getting better."
The economy has been battered by a decline in the value of Ukraine's steel and chemicals exports that has hammered the hryvnia currency, slashed budget revenues and undermined the domestic banking system.
Regardless of the outcome of Sunday's election, squabbling and intrigue were set to continue.
Before polls closed, Tymoshenko's camp said it would contest results in around 1,000 polling stations in the eastern Donetsk region, the industrial power base of Yanukovich.
Deputy Prime Minister Oleksander Turchynov, Tymoshenko's campaign chief, complained of multiple voting and bribery.
Volodymyr Mayevsky, head of the Interior Ministry's public security department, told a news conference that voting "got underway smoothly, without blatant violations of public order" but Tymoshenko's team took a different view.
Investors want a new president who will be able to resume borrowing from the International Monetary Fund (IMF). The IMF put lending on hold in frustration at political squabbling and concerns about budget spending.
The 2010 budget has still not been approved and the country has had no confirmed finance minister since February 2009, when veteran Viktor Pynzenyk resigned saying he could no longer do the job amid the political infighting in Kiev.
(Additional reporting by Dmitry Solovyov in Kiev and Lina Kushch in Donetsk; Writing by Michael Stott in Moscow; editing by Ralph Boulton)