Johanna Konta won a see-saw contest against Anett Kontaveit in the first round of the Abierto Mexicano Telcel.
The British number one, the fourth seed in the Acapulco event, came through 6-3 3-6 6-4 in an hour and 44 minutes in the first meeting of the two players.
Konta, who became the first British woman to make the last four in singles at a slam since Jo Durie in 1983 when she reached the Australian Open semi-finals, was quick out of the blocks.
The world number 26 led 5-1 and although she was broken w hen serving for the first set, she took her chance with the next serve.
The second set was a topsy-turvy affair - Konta broke her Estonian opponent in the first game but was broken back and then broken herself in the fourth game on the way to losing it 6-3.
Konta was up against it when the 20-year-old broke her in the first game of the final set and the third - but she hit back in the fourth and again broke in the sixth.
She then broke Kontaveit in the 10th game to seal the success - aided by the world ranked 91 player's sixth double fault.