By Luiza Ilie, Libby George and Gergely Szakacs BUCHAREST/LONDON (Reuters) -Romanian centrist Nicusor Dan may have defied the odds to win the presidency, but now he faces an even more daunting task: forming a government that can implement years of painful austerity - and revenue-raising measures - to tame Europe's widest fiscal deficit.

Simion, a 38-year-old nationalist who opposes military aid to neighbouring Ukraine and is critical of EU leadership, decisively led the first presidential election round, causing the collapse of a pro-Western coalition government and triggering significant capital outflows.

It was held months after the cancelation of the previous election plunged Romania into its worst political crisis in decades.