RIO DE JANEIRO, April 17 (Xinhua) -- Brazilian swimmer Larissa Oliveira set a South American record in the 200m freestyle on Sunday to secure a berth at this year's Olympic Games in Rio de Janeiro.

The 23-year-old clocked 1 minute, 57.37 seconds at the Olympic aquatic centre to eclipse the previous record of 1:58.03 set by teammate Manuella Lyrio.

The event is serving as both the final Olympic qualifying competition for Brazilian swimmers and an official test event for the newly opened venue.

"I am still in shock. I believe it, but I don't believe it," Oliveira said.

Eight Brazilian swimmers have now qualified for the Olympics, to be held from August 5 to 21.

In the men's 200m butterfly on Sunday, Leonardo de Deus took gold in 1:55.44, the fifth fastest time in the world this year.

In the same event, Kaio Marcio Almeida secured a spot in his fourth Olympic Games.

Monday's schedule was due to feature 50m and 100m freestyle world record holder Cesar Cielo, who is yet to achieve the Olympic qualifying standard for either event.