Photo: Contributed

Ukraine's presidential runoff Sunday is a battle between a billionaire tycoon who rode anti-Russian protests to the nation's top office five years ago and a comedian who plays a president in a TV sitcom. Improbably, the actor appears poised to win.

Comic actor Volodymyr Zelenskiy's commanding lead in the polls reflects widespread disillusionment with President Petro Poroshenko and Ukraine's old political elite, as well as a seething anger against rampant corruption and a lack of opportunity that have left many in endemic poverty.

It also reflects a campaign that has effectively used humour and social media to reach voters.

Zelenskiy's easygoing style and artistic flair contrasts sharply with Poroshenko's stodgy demeanour and stiff gestures, and the rival campaigns bear the distinctive mark of their starkly different persona.