Reizniece-Ozola, a long-time grandmaster, beat Chinese world champion and world number one-ranked player Hou Yifan at the Baku Olympiade run by the World Chess Federation (FIDE) in Azerbaijan.
"In the women's section the biggest attention was attached to the victory of Dana Reizniece-Ozola, Latvia's top board and also the country's Minister for Finance, against the world champion Hou Yifan. China still emerged on the top with wins of Ju Wenjun and Guo Qi," said the official FIDE account of the Round 4 match-up.
A picture posted to social media showed Reizniece-Ozola reacting to her notable victory with disbelief.
@bakuchessol2016 @DanaReiznieceOz uzvar pasaules šaha čempioni Hou Jifaņ! https://t.co/WuLgwkF2Ma pic.twitter.com/0HKWEvz9og
— Matīss (@soikins) September 5, 2016