Olympic champion Cesar Cielo of Brazil has set the world's fastest 50m freestyle time of the year at a short course event in Brazil.

The 27-year-old clocked 20.68 seconds in the semifinal before winning gold later in the day with a time of 20.72 seconds.

The result guaranteed Cielo a berth at the world short course championships in Doha in December.

"They were two very similar races [today]," Cielo said after the event in Guaratingueta, near Sao Paulo.

"Now my focus is on getting my fastest possible time at the world championships."

Italo Duarte took silver in Wednesday's 50m final and Bruno Fratus bronze.

Cesar became Brazil's only swimmer to clinch Olympic gold when he won the 50m freestyle at the 2008 Beijing Olympics.