In the weeks before the Olympics, scandalised reports about the extent of water pollution in Rio’s sea water were everywhere. But nobody imagined it would apply to the shiny waters of the swimming pool.

On a night of deep unease in the Aquatics stadium, the bitter antipathy over Russia's participation in these games and the debate over whether Olympic sports can be believed was reduced to a stark confrontation in the women's 100 metre breaststroke final between Lilly King, the USA's outspoken advocate for a firmer doping system and Russia's Yulia Efimova, who was allowed to compete here despite twice failing drugs tests.

King took gold and the Olympic record (1.04.93), Efimova silver. It was dark, reductive drama based on the old storylines of good versus bad and West versus East.

When the race was over, however, two swimmers were absolutely disconsolate in the bedlam of the mixed zone. Lithuania's Ruta Meilutyte broke down as she tried to explain a deterioration in form which saw her drift from a world record time set three years ago to a sixth place finish here. And Efimova, surrounded by a small town of Russian media, was in tears as she recounted what was one of the most openly hostile receptions ever received by an Olympic athlete.

Booed

She was loudly booed when she had entered the arena, trying to smile and wave and ignore the huge wall of noise directed at her. And after she touched the wall for her silver medal finish, she was completely ignored by the athletes around her.

King, in celebrating, pointedly declined to look to her left where Efimova was treading water in lane five, instead hammering the water’s surface in triumph and then turned to find her American team-mate Katie Meili, who raced to the bronze medal in lane two.

In that moment, Efimova had to reconcile herself to the fact that the medal she had fought so hard to win – she was among the Russian athletes to appeal to the Court of Arbitration for Sport to overturn her ban – had left her a pariah among her competitors. She was only cleared to compete three days ago: now she has a coveted medal.

King was unrepentant after a strange medal ceremony, held after midnight, when the three medallists paraded American and Russian flags in front of a quickly emptying arena, the local crowd already disappearing into a murky evening.

Later, when the three sat down in front of a packed international media presence, King displayed the kind of icy poise that the Democratic elders will hope that Hillary Clinton can muster in the coming months.

“If I was in Yulia’s position I would not want to be congratulated by someone who wasn’t speaking highly of me. But is she did wish to be congratulated by me, then I apologise.”

Shaken

Efimova looked understandably shaken by the events of the evening but held it together as she attempted to give her side of a story which has cast her as being emblematic of everything that is corrupt and ruined within Russian sport.

Irish swimmer Fiona Doyle was frank in her views after swimming in the same heat as Efimova earlier in the week. Since then, Australia’s Mack Horton and Michael Phelps have weighed in on the general debate.

“I understand some athletes who did that. What I don’t understand is that athletes are [supposed to be] out of politics,” Efimova said of the response of the other swimmers.

“That is the tradition. It is upsetting that some athletes watch and read and have no idea of the facts. They can’t imagine what it would feel like if they swapped places with me. There are many athletes who support me: those who know me and who saw me in training. I do all I can and put all my effort in and it is upsetting when politics enters into sport and I would like if athletes could understand one another’s politics.”

When Hajo Seppelt, the German journalist whose television documentary The Secrets of Doping: How Russia Makes Its Winners provoked the World Anti Doping Issue into initiating a detailed examination of internal doping practices in Russia, asked Efimova whether it was fair that she was present in Rio while Yulia Stephanov, the athlete who acted as whistleblower is not, the swimmer shrugged.

“I don’t know what has happens with others because with what happened with me I don’t have time to see what happens with other athletes. I am last four years training in USA and have been in Russia for one month of the year. So I don’t know what is going on in Russia. I don’t know if clean athletes are banned just because they are from Russia. I can’t understand what is going on because sport, Olympic games, they can find a way how to beat Russia and now they try to use athletes and this is so unfair.”

‘Mistake’

Efimova is adamant that she served a suspension for the “mistake” through which she tested positive for DHEA in 2014 but believes her positive for meldonium, a chemical which increases blood flow, in March of this year was not on the banned list when she had been taking it.

“Well...how I feel...right now I feel really happy that I am here and am racing finally. This is the best I can do right now. You just try to understand if you switch and are on my side.”

As the night wore on, it seemed as if both swimmers found themselves as accidental spokespersons for the answers to the deep-rooted problem of doping in sport.

King is 19 and Efimova is 24: presumably they both started swimming, one in Evansville, Indiana, and the other in Grozny with vague dreams fuelled by the vivid technicolour of their childhood Olympics. Now that they both found themselves on the podium and in front of the camera lights, both professed their happiness. But there was very little joy in the room. This was sport at its most political and strained.

The tension and debate is bound to switch to the track when Justin Gatlin, the US sprinter who has served doping suspensions, lines up on the starting blocks against Usain Bolt. King nodded when asked about Gatlin’s presence on Team USA.

“I have to respect their decision even if it is not something I agree with. Do I think people who have been caught for doping decisions should be on the team? No I don’t.”

King’s candour is boundless and Efimova held her nerve through what must have been a harrowing few hours. The medallists filed out of the arena long after midnight and managed to avoid eye contact as they exited in concert, their medals around their necks. They were just feet away but worlds apart.