RIO DE JANEIRO (Reuters) - Brianna Rollins of the United States won the 100m hurdles gold in a time of 12.48 seconds on Wednesday, leading compatriots Nia Ali and Kristi Castlin in the event's first ever Olympic podium sweep.

Ali was clearly in second place when she crossed the line to take silver in 12.59sec but Castlin faced a nervous wait before it was confirmed that she had taken bronze in 12.61sec.

Britain's Cindy Ofili, also born in the United States, pushed Castlin right to the line but lost out on a medal by two hundredths of a second in 12.63sec.

The United States sweep was all the more remarkable given world record holder Kendra Harrison and 2008 Olympic champion Dawn Harper missed the Games after failing to make the cut at the U.S. trials.