World number one and eight-time Miami Open champion Serena Williams was not too downbeat following her shock loss to Svetlana Kuznetsova, insisting she cannot win every match.
Williams and her 20-match winning streak at Key Biscayne came to an end on Monday, dispatched by 15th seed Kuznetsova 6-7 (3-7) 6-1 6-2 in the fourth round.
The 34-year-old had been seeking her ninth title at the WTA Premier event and fourth in a row, but Williams faded in the Miami heat.
Speaking afterwards, the 21-time grand-slam champion told reporters: "I did the best I could. I can't win every match.
"These players come out and play me like they've never played before in their lives.
"I have to be 300 percent every day. It's obviously disappointing, but I have won here a lot, so it's okay."
Williams, who lost to Victoria Azarenka in the BNP Paribas Open final, looked sluggish on court against the Russian veteran.
In two hours, two minutes, Williams tallied 55 unforced errors to Kuznetsova's 15.
Williams also recorded nine double faults, while she only won 39 per cent of her second serves in the three-set battle.
"I don't think it's appropriate to criticise my movement right now," Williams added. "Physically I'm fine. I don't know, I guess I didn't move today.
"Maybe that was one of the things that didn't work out for me."