Fifth seed Samantha Stosur has been knocked out in the first round of the women's Olympic singles to Spanish world number 41 Carla Suarez Navarro.
Despite dropping a service game in the opening set, the Australian broke back twice to clinch it 6-3.
Stosur was broken again at the start of the second but this time she was unable to recover as Suarez Navarro took the set 7-5.
Both players were broke twice in the third before they continued to hold to make it 8-8. The Spaniard held and then broke her opponent for a final time to end the match 10-8 in two hours and 39 minutes.
Suarez Navarro will now meet Belgium's Kim Clijsters in the second round.
