Ukraine prepared Saturday for parliamentary polls in which WBC heavyweight champion Vitali Klitschko has emerged as an unlikely challenger to the ruling party in place of the jailed opposition leader Yulia Tymoshenko.

The ex-Soviet strategic nation of 46 million nestled between the EU and Russia is holding the first election Sunday since Tymoshenko lost to President Viktor Yanukovych in a bitterly-fought contest in 2010.

The firebrand 2004 Orange Revolution leader was jailed less than two years later on abuse of power charges brought by Yanukovych's Regions Party that both Tymoshenko and Western nations saw as vendetta on the part of the president.

Sunday's election to the 450-seat Verkhovna Rada is now seen both as a warm up for the 2015 presidential ballot and a chance for voters to pass judgement on a jailing that has isolated Ukraine from EU states.

Opinion polls suggest that Yanukovych's alliance with the Communist Party and a top centrist politician will retain its narrow lead while Tymoshenko's opposition bloc will grab second place by the slimmest of margins.

But trailing in hot pursuit in third is the UDAR (Punch) party of Klitschko -- an opposition sympathiser who has served in the Kiev city council and now has the chance to expand nationally.

"I have a lot to lose," Klitschko said. "The biggest and most valuable thing that I have is my reputation -- not only in Ukraine but across the world. I have staked the most valuable thing I have on these elections."

A long-mooted alliance between UDAR and the Tymoshenko bloc could give the opposition a parliamentary majority and still further limit the political options of Yanukovych -- already under heavy pressure from the West.

The question of whether Yanukovych will lose his ruling majority depends mostly on whether Klitschko -- assuming the dominant role of kingmaker -- follows through on his promise to work with Tymoshenko's team.

Several analysts noted that Klitschko was now heavily benefiting from voter fatigue with the corruption that has clouded the names of both the president and Tymoshenko in recent years.

"Society is tired of this endless confrontation between Vitya (Viktor Yanukovych) and Yulia (Tymoshenko)," Pravda political writer Sergiy Leshchenko wrote Saturday on their news website. "Klitschko is filling the demand for fresh faces."

Tags: Vitali Klitschko