Chloe Kim said she was "not in a good place" when she woke up for the women's snowboard halfpipe final at the Beijing Games on Thursday - but she certainly was when it was all over. The American sensation overcame a "mental battle" to successfully defend her Olympic title, virtually guaranteeing herself the gold with a scorching-hot start. She claimed an unassailable lead of 94.00 points after her first of three runs, clutching her helmet and dropping to her knees as she slid into the finish area. "I had the worst practice ever - I probably landed my run twice when I'm used to landing it eight times normally and that kind of puts you in a weird headspace," said the 21-year-old. "I just overflowed with emotion when I was able to land it on the first go and then it opened up a lot of opportunity for me to go try something new." Spain's Queralt Castellet took silver on 90.25, while Japan's Sena Tomita claimed bronze on 88.25. Kim gave her rivals little chance of catching her after her phenomenal first-run performance, turning the rest of the competition into her own private victory lap. It gave her breathing space to try some new tricks to a crowd that included California-born Chinese freestyle skiing star Eileen Gu, but she fell on both her second and third runs. "My butt hurts," Kim laughed after attempting an ultra-difficult cab 1260 trick on her final run. "It was worth it though, for sure, a thousand percent. That's what keeps me going. I'm really excited I did it." Kim even had time to embrace Gu after her second run, although the snowboard star described their exchange as "just a lot of screaming and a lot of excitement". Kim became the youngest woman to win an Olympic snowboarding medal when she claimed halfpipe gold as a 17-year-old at the 2018 Pyeongchang Games. She struggled to cope with the pressures of fame in the aftermath and she said Thursday she had learned to accept it was "unfair to be expected to be perfect". "I think the biggest challenge for me now is just to be as open as possible, because I hope that maybe one day a little girl can hear my story and be inspired to keep going, to never give up, to learn that it's OK to have a bad day," she said. Kim was so disillusioned after Pyeongchang that she threw her gold medal in the bin, but she said she "definitely won't be doing that again" with her latest prize. She said she was "really excited for everything that's to come" but refused to commit to future Olympic appearances. She took almost two years off after Pyeongchang, including a year at college partly to experience the normal teenage experiences she had missed out on. "What you guys need to understand is that this isn't an easy sport," she said. "It's all about being smart with it, prioritising my health and just taking it step by step. We'll go from there."