EU leaders on Thursday agreed to start membership negotiations with Ukraine and Moldova, in a major political win for Volodymyr Zelensky.
The unexpected green light came as Hungarian Prime Minister Viktor Orban - who had for weeks said he would block such a deal - agreed to abstain by leaving the room in an unusual move.
Mr Zelensky welcomed the decision, calling it a victory for both Ukraine and Europe.
“A victory that motivates, inspires, and strengthens," he said. “I congratulate every Ukrainian on this day... History is made by those who don't get tired of fighting for freedom."
Ukraine needs support from its Western allies in its nearly two-year fight against Russian forces as its counter-offensive has failed to make major gains.
European Commission chief Ursula von der Leyen said it was "a strategic decision and a day that will remain engraved in the history of our Union."
However, Hungary’s Orban had very different words to describe the decision, calling it “irrational" and "inappropriate."
The talks themselves are likely to take years.
Ukraine, which has a population of 44 million and is geographically bigger than any EU member, presents some unique challenges for admission to the 27-member bloc.
The European Council also decided on Thursday to open accession negotiations with Moldova.
The summit granted EU candidate status to Georgia and will also advance an EU bid by another hopeful - Bosnia - once it reaches “the necessary degree of compliance" with criteria.
Earlier in the day as the 27 EU leaders gathered for their last summit of the year, Orban insisted that the EU should not start membership talks with Ukraine. He was a lone hold-out at the summit.
Other EU leaders had warned that not agreeing to start negotiations would have been seen as a victory for Russian President Vladimir Putin.
Meanwhile, Moldovan President Maia Sandu said Moldova would rise to the challenge to eventually join the EU and was committed to the hard work that lay ahead.
"Moldova turns a new page today with the EU's go-ahead for accession talks. We're feeling Europe’s warm embrace today. Thank you for your support and faith in our journey," Sandu wrote on X, the social media platform formerly known as Twitter.