In Turkey, President Recep Tayyip Erdogan is reeling from a bruising defeat, as opposition candidate Ekrem Imamoglu celebrates a decisive victory in Istanbul's re-run mayoral election. The Republican People's Party candidate narrowly won an initial vote in March, but his victory was controversially annulled by the National Election Commission. CGTN's Michal Bardavid explains how he was able to expand his lead, and win again.

Ekrem Imamoglu, of Turkey's main opposition Republican People's Party CHP, is set to become Istanbul's mayor - again.

Imamoglu initially defeated his rival AK Party's Binali Yildirim during the local election in March with a narrow margin. Objections by AK Party officials of alleged voting irregularities had led to the annulment of the Istanbul mayoral election. This time - the difference is so significant Yildirim conceded just two hours after voting ended.

BINALI YILDIRIM AKP MAYORAL CANDIDATE FOR ISTANBUL "I hope this result will be good for Istanbul. From now on, I hope our friend Ekrem Imamoglu will provide valuable services to Istanbul."

Forty-nine -year- old Imamoglu, a rising star within CHP, is a former mayor of Beylikduzu, one of Istanbul's districts. In his speech Imamoglu emphasized the need to unite the country - and that he would be embracing all of Istanbul, not just the party's supporters.

EKREM IMAMOGLU ISTANBUL MAYOR-ELECT "This is not a victory. This is a new beginning. I would like to say from here that as of tomorrow, I will treat 16 million people equally as a mayor."

MICHAL BARDAVID ISTANBUL "Imamoglu also stressed that he would run things different from his predecessors he promised transparency, to end wasteful spending, and to work with everyone in Turkey no matter their background or political views. He also promised to work day and night to try and solve Istanbul's key issues such as poverty, unemployment and transportation."

Imamoglu also had some messages for Turkish President Recep Tayyip Erdogan. He stressed his readiness to collaborate with Turkey's President on urgent matters related to the country's issues and made a public request to meet with him.

Erdogan had campaigned intensely for AK Party candidate Yildirim. Many analysts believe this defeat is also a major blow - and message - to Erdogan. Once the mandate is formally given to Imamoglu - it will be the first time AK Party and its Islamist predecessors will lose control of Istanbul in twenty-five years.

The win is a huge opportunity for CHP Sunday evening, supporters across the city celebrated with chants and slogans. Winning control of Istanbul, a city that makes up about a fifth of Turkey's population certainly brings a lot of power and responsibility. One that could shape Turkey's political future. Michal Bardavid, CGTN, Istanbul.