When Discovery Bay chiropractor Rick Pierce finished the Bridge to Bridge Sunday, all he knew was that no one else was around, and the lead boat was floating beside him. Thirty seconds later and a judge looking him in the face, he discovered he had won the race.

“I didn’t know for sure,” Pierce said. “I had to ask him what place I got.”

The 6.2-mile race started at the south tower of the Golden Gate Bridge and ended at the Bay Bridge. Although the race is timed so the currents favor the swimmers, the competitors are forced to battle through rough conditions. “This is a swim where the competitor finds different temperatures and different choppy conditions during the race,” said Pedro Ordenes, American and World Coach Association swim director.

Pierce shook off the difficult surroundings, and about 20 other swimmers, to finish at 9 a.m. in 1:31:52.

The course and conditions were so challenging that competitors with limited swimming experience were forced to complete a trial course to ensure their safety.

For Pierce, the win was a culmination of hard work. For the past five months, he swam up to three miles three times per week to condition himself for the rough open-water swim in 55-degree water.

But nothing could prepare him for what he encountered. Pierce said the currents flooding into the bay forced him to change his strategy.

To make matters more difficult, Sunday’s race was the longest of Pierce’s swimming career. In addition to the Bridge to Bridge, he has participated in eight 1.25-mile races.

Pierce didn’t know what to expect when he entered the race, but wanted to challenge himself while doing the best he could. With about a mile to go, however, he realized he was in position to win. “I was tired at the end,” Pierce said. “I felt like I was spinning my arms. I didn’t see very many swimmers around.”

Pierce needed every stroke to overtake the leaders and stay in front, according to Water World Swim coach Noelle Christensen. “The race was really amazing,” she said. “He was not leading the race at first, but he took a different angle, caught the leaders and went right past them.”

Christensen said it takes a special skill set to win open-water competitions, which require swimmers to battle stiff currents and swim when it feels like they’re going nowhere.

“It’s crazy that people actually do this for fun,” Christensen said. “To finish a swim like this is really sweet.”