Great Britain's Elena Baltacha has been knocked out in the second round of the women's Olympic singles by Serbian 11th seed Ana Ivanovic.
The British number four dropped her serve early in the opening set but came to back to level with a break of her own.
With the set heading for a tie-break, Ivanovic broke again to take it 6-4.
Ivanovic looked to be closing in on the win in the second but Baltacha four match points to force the tie-break.
However, the Serb managed to squeeze through 7-4 to set up a third-round match with either Belgium's Kim Clijsters or Spain's Carla Suarez Navarro.
