The 23-year-old delivered a sensational performance in the final round one heat of a busy day to score 15.40 points and advance to the next round.

Defay, who had earlier carried France's flag on stage during the Opening Ceremony, was pleased with her performance.

"Yes it went really good," Defay told insidethegames immediately after.

"I was sitting by myself just on the right of the peak and I caught a couple of good waves.

"Conditions were getting better because it is low tide so it was more hollow and I could do bigger turns."

Joining Defay in the second round will be her compatriot Pauline Ado, who is looking to improve on her bronze medal from last year's Games in Costa Rica.

Ado scored 11.40 to win heat eight.

Other competitors to impress on the first day included Ella Williams of New Zealand and Costa Rica's Leilani McGonagle.

Williams posted a score of 14.03 to finish first in heat 11 while McGonagle eased to victory in heat 12 with 14.70.

More focus will be on Japanese competitors this week as surfing prepares to make its Olympic Games debut in Tokyo in 2020.

Minami Nonaka, who won heat 19 with relative ease after scoring 12.27, believes that with enough training she will be able to compete at the Games in her home country.

"The Olympics are going to be in my hometown so I am going to train a lot and see where that gets me," Nonaka told insidethegames.

"It is all surfers' dream to compete in the Olympics but to have it in my hometown it will be great."

Earlier today, the Games were officially declared open by ISA President Fernando Aguerre.

Following the Parade of Nations, where teams march through the town in which they are competing, surfers participated in the Sands of the World Ceremony with each country bringing sand from their local beaches.

Once each nation had taken part in the ceremony, Aguerre welcomed the 47 nations, the largest field in the event's history.

“Today, as we marched in celebration of our yearly World Surfing Games, I realised that this is the largest ever amount of national surfing teams," he said.

“So congratulations to each of you, to your families and friends back home, and to the tens of thousands of surfing volunteers around the world.

“This is the first World Surfing Games fully impacted by the International Olympic Committee's inclusion of surfing into the Tokyo 2020 Games.

“Our Olympic wave took me personally 22 years of paddling.

“But together we’ve done it and now surfing is both an Olympic and a Pan American Games sport.

“This amazing success, is already influencing the development of surfing all over the world.

“South Korea, China, Afghanistan, Greece and the Virgin Islands are just some of the newcomers to the World Surfing Games.”

It was also revealed in Aguerre’s speech that next year’s World Surfing Games will be part of the Tokyo 2020 qualification process.

However, the ISA have not yet approved a concrete plan.

Action here in Biarritz is due to continue in the women's competition tomorrow.