The 44-year old Gergely Karacsony ousted the incumbent Istvan Tarlos from the Budapest on Sunday’s regional elections in Hungary. That is the first significant political blow to the ruling Fidesz in a decade.

The government of prime minister Victor Orban continues to enjoy a firm grip on power, presiding over strong growth, historically low unemployment, and wage rises. National elections are not due before 2022 and Fidesz commands an overwhelming majority in parliament.

However, Karacsony appears to have snatched a convincing victory in Budapest, securing a 50.6% share of the vote, compared with 44.3% for Tarlos. The opposition also appears to be winning in ten of Hungary’s 23 big cities. The takeaway of this electoral result appears to be the unification of the opposition into a single bloc ahead of the 2022 general election.

“Budapest will be green and free, we will bring it back to Europe,” Karacsony said, comparing his victory to the loss of Istanbul by the ruling AKP in Turkey.

Fidesz run a negative campaign, attacking Karácsony for his allegedly pro-migration stance while prime minister Orbán threatened to withhold cooperation from municipalities lost by his party.