Chad le Clos and Cameron van der Burgh lost their world championship titles just 20 minutes apart in Kazan, Russia, last night. Van der Burgh's defeat was hardly a shock, as he again played second fiddle to world record-holder Adam Peaty of England in the 50m breaststroke.But Le Clos needs to ask himself some questions after failing to overhaul 29-year-old veteran Hungarian Laszlo Cseh on the final leg of the 200m butterfly, the South African's trademark event.That was the race in which Le Clos made his name, stunning Michael Phelps and the planet at the 2012 London Olympics, following that up with the 200m and 100m butterfly double at the last world championships in 2013.But last night he was exposed by a swimmer who had last won a world title a decade ago, when Le Clos was just 13.Now 23, the Durban star went out hard and held the lead for two laps, and then Cseh overtook him in the third 50m and ground out a commanding lead.Le Clos made up ground over the final quarter, but he left his final charge too late and missed out by two-tenths of a second.Cseh, who clocked 1min 53.48sec, said he had changed coach and training method for the final fling of his career.Le Clos, who will attempt to defend his 100m fly crown on Saturday, can take heart in that his 1:53.68 was his fastest time since the 1:52.96 he recorded in 2012, although it's still far off the 1:51.51 world record he has eyed.Van der Burgh touched in 26.66 but it was not enough to beat Peaty (26.51).The silver means Van der Burgh now boasts consecutive 50m medals from the last five world championships dating back to 2007, making him second only to Phelps, with six straight 100m fly medals. ..