Tom Dean admitted winning Olympic gold seemed a "million miles off" when he contracted coronavirus for a second time at the start of this year.
Dean produced the performance of his life in the final of the men's 200 metres freestyle, clocking a national record time of one minute and 44.22 seconds to pip Tokyo 2020 flatmate Duncan Scott in a historic one-two for Team GB.
But there were moments where he wondered whether he would even make the plane to Japan. Having had a mild bout of coronavirus last September, Dean revealed there was scrutiny on him after he tested positive again in January.
"It's probably the biggest medal of my individual career, yeah," he added. "I've won Commonwealth and European but I wouldn't say that's matched by an Olympic medal, the pinnacle of our sport, so yeah I'm delighted."
Both Dean and Scott have little time to revel in their achievements as they are expected to compete in the men's 4x200m freestyle relay heats on Tuesday.
Kathleen Dawson missed out on a medal in the women's 100m backstroke following a sixth-place finish 1.23s adrift of winner Kaylee McKeown, with the Australian's time of 57.47 an Olympic record.
Abbie Wood and Alicia Wilson sealed their places in the women's 200m individual medley final but Freya Anderson finished outside the qualifying places for the women's 200m freestyle.