Lily King narrowly beat her rival, Yulia Efimova, stoking the controversy over revelations of Russian state-sponsored doping
Doping tensions in Olympic swimming erupted after American Lilly King beat tainted Russian rival Yulia Efimova and US superstar Michael Phelps demanded life bans for swimmers with a drug record.
Booing broke out in the swimming arena on Monday as Efimova -- twice convicted of doping but securing an Olympic place on a last-ditch appeal -- lined up to challenge the women's 100m breaststroke final.
King narrowly beat her then, stoking the controversy over revelations of Russian stated-sponsored doping.
"I think it just proved that you can compete clean and still come out on top," King said of her win. She had also criticised Efimova before the race.
Russia springs to defence
Clearly devastated, Efimova burst into tears after the race.
Russia sprang to her defense, with Sports Minister Vitaly Mutko describing her as a "good girl", according Moscow's R-Sport news agency. The attacks were described as a "terrible ordeal."
The red-faced International Olympic Committee (IOC) sought to calm the choppy waters, saying the Games were about "respecting the right of others to compete."
But King was joined in the war of words by US legend Phelps and Frenchman Camille Lacourt among others who lashed out at a Chinese winner.
Phelps, who will attempt the astonishing feat of winning his 20th Olympic gold medal later Tuesday, launched a broadside at drug abusers and encouraged others to speak out.
Phelps said those punished for doping should face permanent exile from the sport.
"I think you're going to see a lot of people speaking up more," the all-time highest Olympic medal winner said.
China's Sun Yang, who won the 200m freestyle on Monday, came under fierce attack from a furious Lacourt.
"Sun Yang, he pisses purple," an enraged Lacourt who came fifth in the 100m backstroke told French radio. "When I see the 200m podium I want to be sick."
Sun has already been at the center of a verbal battle with Australia's Mack Horton who beat Sun in the 400m race.
The Sun-Horton dispute has turned into a social media war. China's state-controlled Global Times newspaper called Australia a former British "offshore prison" because of Horton's "drug cheat" remarks about Sun.
'I once made a mistake'
Efimova sought to defend her doping record.
"I once made a mistake and served my ban," she said, referring to a 16-month suspension incurred after testing positive for a banned steroid in 2014.
She was given a provisional ban this year after testing positive for meldonium but that was overturned in May by the Court of Arbitration for Sport (CAS).
Following the Richard McLaren report for the World Anti-Doping Agency, Efimova was suspended again. The report implicated the Russian government in doping.
But another appeal to the CAS last week let Efimova and six other Russian swimmers into Rio.
The United States and other western countries had wanted a complete ban on Russian athletes.
The row largely overshadowed a day that saw a first gold medal for the Brazilian hosts. It was won by judoka Rafaela Silva, who grew up in Rio's notorious City of God slum.
Silva upset world No. 1 Sumiya Dorjsuren in the 57kg final for a hugely welcome win for Brazil after apathy and protests in the run-up to South America's first Olympics.
China got more medals in diving, where Chen Aisen and Lin Yue won the men's 10m platform. China finished the day with five gold medals in total.
Japan's 'King Kohei' Uchimura led Japan to victory in the men's team gymnastics, completing his collection of major titles in the sport.
Russia took gold and silver in the women's sabre fencing as Yana Egorian beat Sofiya Velikaya, who again suffered heartbreak after also losing the 2012 Olympic final.
Thailand enjoyed a one-two in the women's 58kg weightlifting as Sukanya Srisurat beat Pimsiri Sirikaew by 8kg.
And in rugby, Australia's women beat New Zealand to become the Olympics' first rugby sevens champions.