When you've spent months training for the Ironman World Championship in Hawaii, the last thing you want in the warm-up is to be stung by a jellyfish.
Not once, but twice.
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"I tried to convince myself that it didn't happen but obviously I could feel it very quickly. It felt like having fire under my arms," Daniela Ryf told CNN Sport.
The searing pain before even starting the grueling event -- in which athletes take on a 2.4-mile swim, a 112-mile bike ride and a marathon (26.2 miles), all under a scorching Hawaiian sun -- might have derailed many participants.
But the 31-year-old Ryf is one of a kind, and the Swiss refocused from her jellyfish encounters to clinch her fourth consecutive Ironman title last month.
"A bit of me wanted to go back to the hotel and cry but I thought that wouldn't really help much," said Ryf. "My team invested so much time to help me achieve everything. The race was my turn to give back."
The "crazy" day rapidly improved for Ryf when she got out of the water and no longer needed her arms as much.
She set a bike course record to make up the 10-minute deficit and extended her lead during an impressive run. Her efforts culminated in a new course record of eight hours and 26 minutes.
Kailua-Kona, Hawaii, has hosted the annual Ironman World Championships for the last 40 years and the event has a special place in Ryf's heart.
Since winning her maiden title in 2015, the Swiss is unbeaten on the course.
As a result, she's developed a spiritual bond with the island and is already looking forward to returning next year.
"Whenever I go back to Kona, it will give me goosebumps," she said.
'Giving up isn't an option'
Ryf struggles to explain what makes her better than everyone else. The truth is, it's a number of things.
She has a pragmatic approach to everything she does, whether that be training, eating or competition.
She has an incredible mentality which has helped her push through the pain barrier on countless occasions and remain positive throughout her glittering career.
"If giving up isn't an option, you don't have to think about it," she said. "You then just need to figure out how to keep going.
"The body only does what the mind tells it to do. I told myself I wouldn't give up and that I'd be the champion."
'The longer stuff'
Ryf comes from an active family. Her father was a rock climber and her mother used to run marathons.
She remains eternally grateful for their support in the early stages of her career, even though she admits to never having aspirations of being world champion.
Ryf started swimming and running when she was nine years old and initially saw training as just a chance to see her friends.
Things started to become a little more serious when she joined a triathlon club at 13.
"I then started to enjoy improving and that's still the same. I enjoy that feeling when your body gets stronger and fitter," she said.
The young triathlete flourished, and she was selected to represent Switzerland in the 2008 Olympics in Beijing, finishing seventh over the Games distance of 0.93 miles of swimming, 24.8 miles on the bike and a 6.2-mile run .
A second Summer Olympics followed four years later but Ryf was always drawn to the "longer stuff."
The grueling regime
Under the guidance of current coach Brett Sutton, Ryf stepped up to Ironman competitions. The pair haven't looked back since.
Enjoying training is another factor behind her rise to the top of the sport.
Ryf usually dedicates herself to three sessions a day, the first starting at 7 a.m. on an empty stomach.
She then eats breakfast and rests before two more grueling sessions at 11 a.m. and 4 p.m.
She admits it can be "boring" but is able to switch around the training sessions to keep her interested.
Ryf's love for training is borne from her curiosity. It's what drives her to continue training during the off season.
"It gives me something that makes me feel happy. I find it inspiring to see how your body gets stronger and fitter," she says.
Ryf also enjoys changing the location of her base.
Ahead of the success last month, she spent three months in the Swiss mountains before an additional four weeks training in the heat of Maui, Hawaii.
But no matter where she trains, she always aims to be efficient.
"It's not about how hard you train but how well you train," she said. "If you're prepared well, then you will be able to cope with the challenges in the race."
Chocolate and burgers
She applies a similarly pragmatic approach to her diet. Ryf uses huge amounts of energy on a daily basis, and how she eats is vital for refueling her body but also how she feels emotionally.
"I think it's about having that balance," she says. "Sometimes I eat chocolate or a burger that makes me feel good. I don't have to restrict myself too much."
Unlike Patrick Lange, the winner of the men's division in this year's Ironman World Championships, Ryf is not a vegetarian. She believes meat, as well as fruit and vegetables, is important for her recovery.
"I try to keep it balanced which makes me the happiest. If you're happy, you're more balanced and your performance is better," she said.
Ryf is enjoying some downtime after yet another successful season but is already looking ahead to defending her title next year.
"It's pretty clear that I want to go back, it's not really a question," she said. "I've still got lots in me and I want to show more."