Australia has made a disastrous start to rugby union's World U20 Championship in Italy with an embarrassing 73-17 loss to South Africa in its opening match. As the Wallabies prepare to host the British and Irish Lions in a three-Test series, Australian rugby's next generation of stars were given a reality check at Stadio San Michele, Calvisano. Coached by ex-Wallabies scrum-half Chris Whitaker, Australia conceded 11 tries. Fullback Sid Harvey scored a try and conversion for Australia, while winger Cooper Watters crossed for a double. South Africa led 33-5 at half-time. The final scoreline came as a shock to many observers, given Australia defeated South Africa 29-24 in the four-team U20 Rugby Championship in Port Elizabeth last month. New Zealand and Argentina also contested the tournament in South Africa. Australia faces Scotland in its second World U20 Championship pool match, which will be played in Viadana on Friday night AEST. The Australians finished sixth at last year's tournament, hosted by South Africa. They have twice reached the World U20 Championship final, most recently in 2019. The 2019 squad included Wallabies captain Harry Wilson, as well as the likes of Fraser McReight, Angus Bell, Noah Lolesio and Mark Nawaqanitawase.