China's Ju Wenjun retained her Women's World Chess Championship title after beating Russia's Kateryna Lagno in a tie-break in the Russian town of Khanty-Mansiysk on Friday.

This makes the 27-year-old the first woman in history to defend a world title in a knock-out championship.

The first two 25-minute contests ended in draws, but Ju managed to win the two 10-minute “blitz” matches.

Yu Shaoteng, head coach of China's women's national chess team, said Ju deserves the title: "She played really well. She had a strong heart to stay calm when she was behind her opponent. It is not easy for her to win." 

Ju won the Women's World Champion by beating her compatriot Tan Zhongyi in May.

Although Lagno lost, she has qualified for the 2019 Women's Candidates Tournament, and the winner will face Ju Wenjun.