British number one Elena Baltacha crashed out of the Sony Ericsson Open in Miami after a second-round defeat to 32nd seed Klara Zakopalova.
The unseeded Baltacha fought back impressively to beat Sybille Bammer in the first round but she was unable to continue her form against the Czech, who won 7-6(4) 6-3.
Both women managed two breaks each in the first set but Baltacha was outfoxed in the tie break.
She was broken twice in the second though and only able to break her opponent once in return, meaning Zakopalova awaits the winner of sixth seed Jelena Jankovic and Monica Niculescu in the third round.
"She’s a good player," Baltacha said afterwards. "She’s a seed here and she’s had some big wins and I knew that I had to play unbelievably well to stand a chance.
"In the first set I got myself into a tie-break despite being down a break a couple of times, but then I just gave her some loose points. After that she stepped it up. It was definitely a lot better than our last match (in Doha last month).
"Overall this week has been a real positive for me. I learned a lot from today’s match. There are weaknesses in my game that I need to improve, and areas that I need to get better in, and that’s the most important thing to focus on after a loss.
"At the same time, though, I’ve also learned how much I’ve improved."