Georgian president Mikhail Saakashvili has conceded defeat in parliamentary elections and said the opposition now had the right to form a government.
He said: "It's clear from the preliminary results that the opposition has the lead and it should form the government. And I as president should help them with this."
Early results showed an opposition coalition led by billionaire businessman Bidzina Ivanishvili with what appears to be an insurmountable lead as voters turned away from Mr Saakashvili and the party that has been in power for almost nine years.
Mr Ivanishvili confirmed he would take up the post of prime minister.
Mr Saakashvili's concession of defeat even before the election results were released preserved calm on the emotionally charged streets of the capital, Tbilisi, where support for the Georgian Dream coalition is strongest. Opposition supporters had boisterously celebrated throughout the night. If they had felt deprived of victory, the mood very quickly could have turned hostile.
During his nearly nine years in power, Mr Saakashvili has pushed through reforms and attracted international investment that has led to dramatic economic growth. Poverty and unemployment, however, remain painfully high.
Georgians have turned against Mr Saakashvili in recent years. Many accuse his party - which has controlled not only the government and parliament but also the courts and prosecutor's office - of exercising authoritarian powers.
Mr Saakashvili will remain the leader of the country until his second and last term ends next October. Under a constitutional reform that goes into effect after he leaves office, many of the president's powers will be transferred to the prime minister, who is chosen by parliament.
This is the first time in Georgia's post-Soviet history that a government will be changed by the ballot box rather than through revolution. Mr Saakashvili came to power through the peaceful Rose Revolution after a rigged parliamentary vote in 2003.
Mr Ivanishvili has stated his commitment to pursue Mr Saakashvili's goals of making Georgia an integral part of Europe and member of Nato, while adding he will seek to restore the trade and diplomatic ties with Russia that were severed when the two countries fought a brief war in 2008. Georgian producers of wine, mineral water, vegetables and fruits had depended on exports to Russia, and the closing of these markets hurt them deeply.