Lilly King has no regrets about calling out drug cheats at the Olympic Games in Rio de Janeiro.

King grabbed international headlines when she was filmed wagging her finger at the television screen after watching her Russian rival Yulia Efimova — who had tested positive for a banned substance prior to last summer’s Games — win her 100 metres breaststroke semi-final.

The American swimmer’s fiery gesture, a response to Efimova mimicking King’s raised finger to signify she was No 1 earlier in the day, captured the world’s imagination, with the media unsurprisingly ramping-up the pair’s “Cold War” battle before the final.

King, who has spent the past week in Bermuda with her Indiana University team-mates training at the Aquatics Centre, went on to win the gold medal, beating Efimova by more than half a second and setting an Olympic record of 1min 04.93sec in the process.

As far as King was concerned her foe should not have been competing in Rio. Although she has since admitted that her colourful antics were also a calculated effort “to get inside Efimova’s head”.

“It’s a lot of fun, stirring stuff up,” King told The Royal Gazette. “In swimming you don’t get too much confrontation and I’m all for it.

“I’m not going to do anything unless I need to, though. Not unless it’s necessary.”

King did indeed feel that taking a stand on doping was necessary.

The 19-year-old also criticised Justin Gatlin and Tyson Gay — the 100-metre runners and team-mates on the United States Olympic squad, who have both failed drug tests — and is steadfast in her belief that there is no place in sport for performance-enhancing drugs.

“I think I made it easier for myself, speaking my mind, because after every single race I wouldn’t get asked about my race, they would ask me about [Efimova], whether she should be competing.

“I was like, ‘I’m not this person, you should be asking me about my race and how it felt for me. After I spoke out, it was a lot easier to go on with my meet and with my life. I don’t regret what I said; I did it and it needed to be said.”

As soon as Efimova was cleared to swim just days before the race, the hype surrounding her rivalry with King began to intensify — even before the American’s now-infamous finger wag.

King admits that she was slightly overwhelmed by the reaction and believes it hindered her performance in the 200 where she failed to reach the medal race, placing seventh in her semi-final.

“After the 100 final it really distracted me, my phone was constantly blowing up,” King added. “I’d never had that sort of following before and all of a sudden everyone at home knows my name.

“It was definitely a distraction for my 200 and my [4x100] relay at the end of the week. It was distracting and exhausting at the time, but I’ve learnt to deal with that now.”

Controversy aside, King could have hardly hoped for a better 2016. In her freshman year, she was crowned the NCAA Division I champion in the 100 and 200, setting American and NCAA records, as well as being named the Big Ten Freshman of the Year.

At the US Olympic Trials she won both of her events to further fuel her belief that a medal in Rio was well within her reach.

“I couldn’t have really asked for a better year,” said King, who is staying at Warwick Camp with 72 team-mates and nine coaches.

“I started with the NCAAs, setting a pair of records, and that was a pretty big deal, especially as a freshman.

“Every single thought was about making the Olympic team and by May it hit me that I could win a medal. Isn’t that the highlight of everyone’s career? I could basically retire now.

“Winning a gold medal is great, but I’m still trying to move past that and set new goals and move forward to the future.”

King has struggled for motivation since Rio and was not at her best at the world short-course championships in Windsor, Ontario last month, although she still claimed gold in the 50m breaststroke and three relays.

“I’ve definitely been having motivational issues since coming back from Rio,” said King, who will defend her titles at the NCAA Championships in Indiana in March. “I really didn’t think I would, but it kind of hit me when I got to the worlds and I was like, ‘Oh, this is not the same as it has been’. But I’m starting to get back into it and the hard training. I’m getting back to where I was earlier last year.”

Mike Westphal, the Indiana associate head coach, has accompanied the team — which includes Olympic medal-winners Blake Pieroni and Cody Miller — to Bermuda.

He said that not only does King have the talent, she also possess the intangibles: the drive, passion and dedication that set her apart.

“When she gets something stuck in her head, she is just determined to make it happen,” Westphal said. “She convinced us that she was going to win a medal when she came in as a freshman. There was no doubt about it; it was going to happen. She’s also ultra competitive and that always helps.”

Westphal said that the Indiana coaching staff fully supported King’s move to speak out against doping at the Olympics.

“The world nowadays is more politically correct and she’s someone who will speak her mind,” he added. “We support that, we’re OK with that.

“The support she had on the US side was very positive. On the Russia [side], not so much. She showed me some of the stuff she received on Twitter from the Russians — that was a little bit different!

“From the rest of the world, though, I think it was positive. They don’t want doping in the Olympics or amateur sport.”

With her best years still ahead of her, it is unlikely King will shy away from speaking her mind any time soon.

They probably could not stop her even if they tried.