On the eve of Hungary's bitterly fought and highly significant election, the two main rivals are taking their campaigns to the wire, as Péter Magyar attempts to end 16 years of continuous rule by Viktor Orbán's Fidesz party.

"We're at the gates of a two-thirds majority victory. Let's gear up and push for the last 100m!" he told cheering supporters, before mingling for selfies.

His final campaign stop will be in the second city, Debrecen, in the north-east, while Orbán, who trails in most of the polls, will address a rally in Budapest.

But perhaps the biggest rally of all came on Friday night, when tens of thousands of Hungarians crammed the capital's Heroes' Square and surrounding streets for an anti-Fidesz concert.

"I feel it in my bones something's going to change," said first-time voter Fanni, who came with her mother from a village two hours' drive away in the south. "I don't believe I'd vote for [Magyar] in an ideal situation, but this is our only chance."