Chad Le Clos, who equalled Ian Thorpe's Commonwealth Games record haul of seven medals, has revealed his preparations for Glasgow were wrecked by illness.
Le Clos, 22, suffered from asthma and admitted he was "in shocking form" in the weeks before the competition.
"I was on three different pumps and struggling, and not entirely confident coming to these Games," he said.
Despite his health concerns, the South African swimmer won two golds, a silver and four bronze medals.
Le Clos added: "I tried to keep my illness under cover as I didn't want to let the opposition know I was a bit down.
"There was no way I could have got any more medals. I did the best I could and I am really delighted and proud of myself at the way things have turned out."
Meanwhile, Le Clos welcomed the return of Michael Phelps, after the American great announced that he is coming out of retirement.
Le Clos, who famously beat Phelps in the 200m butterfly at the London Olympics, said: "I am super looking forward to it. I hope he swims all the races that I swim so we can have a rematch."