American Kristin Armstrong is the Olympic Women's Time Trial champion for the third time
A cloudy day with some rain in Pontal for this 29.8km time trial which had attracted 25 entrants.
Anna Plichta of Poland was first down the ramp on this one lap of the Grumari circuit which featured in Sunday's road race at 8.30am local time.
Great Britain's Emma Pooley went down the ramp at 8.45 and approached the opening kilometres cautiously whilst Tara Whitten of Canada was charging up the road as was Elisa Longo Borghini who was fastest by six seconds at the first checkpoint.
Ellen Van Dyjk ended up in the jungle shrub as Whitten went through the second checkpoint in 33.08.
Ann Plichta was first to finish and went in to the hot seat with a time of 47.59.66 that lasted until Eri Yonamine (Japan) came home in 46.43 with Tara Whitten finishing in 45.01.
Emma Pooley was Britain's hope for a medal but that was dashed as she finished in 46.31 and she said that she gave it her all but it was not her day.
Elisa Longo Borghini took over the lead with a time of 44.51.34 until Ellen Van Dyjk came over the line in 44.48 and then Russian Olga Zabelinskaya finished in 44.32.
Forty year old and Olympic champion Kristin Armstrong put in a superb ride and she finished in 44.26.42 to take the Gold Medal.
Result
1 Kristin Armstrong 44.26
2 Olga Zabelinskaya 44:31
3 Van der Breggen 44:37