Advertisement Victoria’s first mystery coronavirus case in more than two months will intensify pressure on the state’s testing and contact tracing system after thousands of Boxing Day shoppers at Chadstone shopping centre and cricket spectators at the MCG were potentially exposed to the virus. Authorities are on high alert after a man in his 30s who attended sales at Chadstone on December 26 and the MCG Boxing Day Test match on December 27 later tested positive to COVID-19. Some of the tens of thousands of people who visited Chadstone Shopping Centre on December 26 for the Boxing Day sales. Credit:Getty Images