Super Bowl Sunday was truly XL for North Shore surfers Garrett McNamara and Kealii Mamala.

McNamara and Mamala won the North Shore Tow-In Championships in extra-large waves off Hale'iwa's Puena Point Sunday.

"It was the best day I've ever seen out there," McNamara said. "Conditions were just perfect."

Traditional wave heights were estimated at 15 to 20 feet, so the wave faces were around 30 to 40 feet.

In tow-in events, each "team" features two surfers — one operates a personal watercraft, and the other surfs. The power of the watercraft pulls the surfer into the giant waves.

Eighteen teams from around the world entered Sunday's event.

"The key is to have real good communication with your partner," McNamara said. "We talked about everything we wanted to do and we did a warm-up thing that morning."

Before the start of the contest, McNamara and Mamala practiced in even bigger waves off Sunset Beach.

"There were some 50-, 60-foot faces in the morning," Mamala said. "So by the time we got to Puena Point, we were ready."

In the contest, McNamara and Mamala alternated every two waves — McNamara would operate the watercraft for two waves while Mamala surfed, and then they would swap positions.

In the final heat of the contest, Mamala received the highest scores for his rides. On his best ride, he said he completed several maneuvers along a giant barreling wave that was "maybe 100 to 150 feet long."

"Garrett put me in perfect position for the wave, and then the wave just set up perfect," Mamala said. "I wouldn't say it was the wave of my life, but it was definitely a wave that helped us win the contest."

McNamara, 38, and Mamala, 27, received $5,000 for the victory.

They took the money and ran — chasing the giant swell to California.

On Tuesday, McNamara and Mamala had a tow-in session in 20-foot waves at a spot called Shark Park off Santa Barbara.

"We actually were riding the same swell in California that we rode in Hawai'i," McNamara said. "We're on a really good roll as a team right now, so we want to keep it going."

Reach Dayton Morinaga at dmorinaga@honoluluadvertiser.com.