O'Callaghan upstages Olympic champion Titmus as McKeown challenges world record

Kyle Chalmers was also in blistering form at the Australian championships, swimming a lightening 100m free to lay down a marker ahead of the Olympics. O'Callaghan hit the wall on the Gold Coast in an eye-popping 1min 53.57sec, with an explosive last 50 pulling her away from Titmus, who touched second in 1:55.38. "I'm always striving to go fast," said O'Callaghan, who also won the 100m title. "The 200 is a difficult event to work out and this was the last time to get it worked out before trials."...