Ranomi Kromowidjojo of the Netherlands blazed to gold in the women's 100 meters freestyle on Thursday, setting a new Olympic record.
Kromowidjojo, who led the timesheets this year, posted 53.00 for gold but was not happy with her performance.
""I thought it was a great race but it wasn't a PB, it wasn't my best time ever this season so I'm not really satisfied about the time," she said.
"A gold medal is a gold medal, so I'm really happy about my medal and being Olympic champion."
Aliaksandra Herasimenia of Belarus sneaked in for silver in 53.38 ahead of Tang Yi of China, who clocked 53.44.
America's Missy Franklin finished a disappointing fifth.