World number three Jelena Jankovic, eliminated in the second round for the second tournament in a row, said she had lost her confidence after a poor start to the season.
The Serb, semi-finalist in all four grand slams last year, was beaten by Argentine Gisela Dulko in the second round of the Sony Ericsson Open and was unsparing in her self-criticism.
"For the last three months, I haven't been playing well at all. I've been losing to the players because I'm just not at my level," she told reporters.
Before the tournament at Key Biscayne, the 24-year-old Jankovic, who also went out in the second round at Indian Wells, blamed her poor form on her attempt to bulk up and improve her strength.
Using words such as "complete breakdown" and lamenting the loss of her powerful return, Jankovic was clearly not expecting great things in Miami but she was still upset by her loss.
"I'm not the same player as I used to be. I haven't been moving well and I changed all these things. I lost a couple of matches which for a player of my calibre it's not really acceptable and so I lost a little bit of confidence," she said.
"I need to find the habit of winning matches even when I'm playing poorly, tired or not tired, even when I don't feel the shots, whatever it is.
"Hopefully, I'm going to find that confidence and the whole construction of my game sometime soon," she said.
Having suffered on the hard courts, Jankovic is now hoping that the switch to clay could lead to a revival in her fortunes.
"Hopefully, I will begin my season, because I still haven't begun at all and I hope I can do it on the clay," she said.