It was the biggest fight of Stacey Copeland’s professional life up to that point, and she couldn’t stop shivering.

As she walked into the arena, her teeth chattered and her body shook. She worried about the gap in experience between herself and her opponent.

She’s been to the world championships, Copeland told herself. I’ve barely even been in 10 fights.

Copeland, a professional boxer who went on to become the first British woman to win the Commonwealth title, had spent the previous week reading stories about her opponent. All the stats, quotes and headlines only fueled her fears, leading her to imagine the worst: What if my legs give out or my arms don’t work?

Physically, she felt so horrible that her mind started to believe those thoughts, no matter how ridiculous they sound in hindsight. By the time she walked into the arena, she was terrified.

Not surprisingly, she lost the fight.

Later that day, she watched footage of the fight, and it wasn’t until that moment, when she saw herself on screen, that she finally saw what happened to her.

“I realized I boxed small,” Copeland said. “I boxed while being really fearful of her rather than doing my best. I was really, really disappointed in myself in a completely different way than how you would be if you’d given it your best and you lost.”

That moment sparked something within Copeland. She knew how to improve her boxing skills. But she needed to understand why fear had such a grip on her and how she could stop it from ruining her hard work.

In the years that followed, Copeland began to study fear. She read books, spoke to others, mentored younger fighters and became an advocate, openly sharing her experiences and best practices.

Boxing is a particularly effective sport for discussing how to deal with fear.

“Your brain should try and talk you out of fighting another human being and getting punched in the head,” Copeland said. “That’s the right thing for your brain to do, but, obviously, you just have to control it.”

Here are her three most effective methods for dealing with fear:

Put it in the trunk

When Copeland was spiraling, she didn’t realize how her thoughts were hurting her. She was in a fight-or-flight mode, and her mind was doing its best to protect her. That doesn’t mean those thoughts were helpful.

Once she realized that she could accept her thoughts as unhelpful, it allowed her to devise a trick: She started to visualize picking each thought and throwing it in the trunk of a car. Then, in her head, she parked the car, locked it and walked away.

“If I was starting to allow them to drive, no, they have to get in the back,” she said.

You can’t get rid of bad thoughts. But you can recognize them for what they are, pack them away and replace them with new ones.

The take-away method

Later on, Copeland began mentoring younger fighters. Before a big fight, she noticed one of them shaking and hyperventilating. She knew what was happening: Fear was taking over. The fighter explained that she didn’t want to step into the ring.

“You’ll be fine once you get in there,” Copeland told her. “You’ve worked hard for this.”

Nothing fixed it. A few minutes later, another coach walked in to check on everyone, and Copeland pulled her aside to explain the situation.

Without hesitating, the coach walked over to the young fighter and asked if she no longer wanted to box. When the fighter said no, the coach told her that it was fine; that she would let everyone know. There were loads of people who would love this opportunity, and she didn’t want to force anyone to do something they didn’t want to do.

“No problem,” the coach said and walked away.

Copeland was baffled. About 30 seconds went by before the fighter got up and pleaded to fight. When Copeland went to tell the other coach, she found her waiting on the other side of the door, ready for this moment that she knew would happen.

“Is she ready to fight now?” the coach smiled.

These days, Copeland uses that strategy herself. She calls it “the take-away method.” If she is nervous, she thinks, “Would you want this opportunity taken away from you right now?”

If the answer is yes, she knows she either isn’t ready or this isn’t the right time for her. But if the answer is no, it’s a comforting reminder that she is experiencing healthy and perhaps even productive nerves as she prepares for something she cares deeply about.

Remember your why

When Copeland was getting ready to fight for the Commonwealth title in Zimbabwe, a championship match that symbolizes elite status for fighters from Commonwealth nations, she felt the same, familiar feelings kick in.

“Like electricity going through every cell and vein in my body,” she said.

She also had some of the same thoughts: What if my legs and arms don’t work? She tried to snap out of it with her two tactics — the trunk visualization and the take-away method — but neither worked. Not even a little bit.

“What the f— am I doing?” she said to herself. “Why am I even here? What is the point of fighting this scary woman who wants to punch my head in?”

The more she went back and forth with herself, the real “why” came to the surface: her 11-year-old self.

Copeland’s father and grandfather were both boxers, and she enjoyed training as a child. The Amateur Boxing Association (now England Boxing) didn’t lift its ban on women’s boxing until 1996.

“That little girl, when I was 11 and I was told I wasn’t allowed to box,” Copeland said, “she’d have given anything — anything to be in this position.”

That one thought began to fuel her.

“How dare you,” she said to herself. “How dare you s— yourself now and panic instead of giving your absolute best for that little girl who would give anything to be here.”

Deep down, Copeland wanted to challenge herself. She loved challenges. It’s one of the reasons she fell in love with fighting. She should want to put herself against the best in the world to test herself.

She won the title and discovered a new tactic. By simply remembering her purpose, she drove away fear and replaced it with strength.

In that moment, she understood: Fear was only as intense as she allowed it to be.

(Illustration: Dan Goldfarb / The Athletic; Sportsfile / Corbis/Sportsfile via Getty Images)