Venus Williams and Serena Williams are still the faces of American tennis, but the future of the sport might be 15-year-old Cori “Coco” Gauff, who grew up idolizing the sisters.

During the opening round of Wimbledon on Monday, Gauff upset Venus Williams, who was 24 and already a 2-time Wimbledon champ when Gauff was born.

After the win, Gauff was asked how she was able to remain so calm and composed during the biggest match of her career so far. Gauff cited a mental trick for underdogs made famous by the fictional high school basketball coach Norman Dale in the movie “Hoosiers.”

“I’ve never played on a court so big,” Gauff said. “I had to remind myself that the lines on the court are the same size. Everything around it might be bigger, but the lines are the same. After every point, I was just telling myself to stay calm.”

In “Hoosiers,” Dale’s team from tiny Hickory, Indiana reached the state championship game where they would face a squad from a much larger school in an Indianapolis gym much bigger than anything they had ever played in before.

When the team first arrives in Indianapolis, Dale takes them to the arena and, using a tape measure, shows the small-town players that the basket is the same height, and the lines are the same distance as their tiny gym back in Hickory.

Hickory went on to win the state championship.

Gauff might not be ready to win Wimbledon, but she’s got the right attitude, and it already helped her upset one of the best tennis players of all time.

Originally published on Business Insider.

More from Business Insider:

Alexis Ohanian has taken out billboards for wife Serena Williams, but he says a simple Sunday morning ritual means more to their relationship

An organizational psychologist has a sneaky job-interview question to figure out what it’s really like to work somewhere

Melinda Gates has some great advice on how working parents can reduce stress

Follow us here and subscribe here for all the latest news on how you can keep Thriving.

Stay up to date or catch-up on all our podcasts with Arianna Huffington here.