RIO DE JANEIRO — The sewage-filled waters off Copacabana weren’t much of an issue for the open water swimmers.

“It tastes like ocean,” American Haley Anderson said nonchalantly.

Instead, the women’s Olympic race will be remembered for something more familiar in the rough-and-tumble sport – a disqualification right at the finish line that lifted Brazil to a bronze, its first swimming medal of the Rio Games.

Sharon van Rouwendaal claimed gold for the Netherlands with a dominating performance, pulling away over the final lap to win in a romp Monday.

Van Rouwendaal began to spread the margin on the third of four laps, and it wasn’t even close by the end of the 10-kilometer race. She reached up and touched the timing board before her closest challenger had even entered the finish chute. The winning margin was a staggering 17.4 seconds, far more than the 0.4 difference four years ago and the 1.4 spread at the inaugural open water competition in 2008.

“I felt so good,” said Van Rouwendaal, who finished in 1 hour, 56 minutes, 32.1 seconds. “I swam so easy. I felt no fatigue. After 6k, I changed my mind and thought I should push on.”

The bigger drama came behind the winner. Aurelie Muller of France touched next, but then it was announced she had been disqualified for an incident at the finish. Apparently confused, she was about to swim into a white buoy when she tried to cut over and collided with Italy’s Rachele Bruni.

“She pushed down my arm,” said Bruni, who wound up with silver.

Brazil’s Poliana Okimoto went from just off the podium to bronze – the first swimming medal ever won by a Brazilian woman, either in the pool or open water. Okimoto’s medal eased some of the sting from a disappointing performance by the pool swimmers, who failed to win a medal at their home Olympics.

Van Rouwendaal didn’t look like much of a medal contender as she battled an ailing right shoulder for eight months. Finally, about six weeks before Rio, she was able to get treatment in Spain that relieved the pain.”It’s not been a great year for me,” she said.

It just got a whole lot better.

Defending Olympic champion Eva Risztov of Hungary wasn’t a contender this time. She finished 13th, more than a minute behind the winner. Anderson, the silver medalist four years ago, was more than 48 seconds off the pace in fifth.