Mollie O’Callaghan stunned Australian team-mate and top favourite Ariarne Titmus to claim gold in the women’s 200-metre freestyle at the Paris Games on Monday. O’Callaghan set a new Olympic record of 1 minute 53.27 seconds to defeat previous record holder Titmus by 0.54 seconds. Bronze went to Hong Kong’s Siobhán Haugheym who led most of the race but couldn’t get the final push. Titmus, who won 200m freestyle gold at Tokyo 2020, already had the 400m freestyle gold in Paris. In the women’s 400m medley, meanwhile, Canadian wunderkind Summer McIntosh blew away her competitors to take gold. The 17…