Serena Williams criticizes herself after losing to former No. 1 Caroline Wozniacki at the Sony Ericsson Open in Miami, the first time she has fallen to the Dane in four tries.

"The good thing is I could've played a lot better," Serena told reporters. "I probably played about 20 percent. You know, it would really suck and if I had to sit here and say I couldn't do any better. That's not the case. I just made a tremendous amount of errors. There's no reason for that. I'm older and I shouldn't do that. There's no excuse. I just gotta stop that. It's silly."