For some reason, Serena Williams trotted back out for another tournament three days after winning the Sony Open. Call it the Tiger Woods syndrome.

Sure, Williams is expected to beat 78th-ranked Jana Cepelova anytime they meet. Only she didn't.

Cepelova stunned Williams 6-4, 6-4 in the second round of the Family Circle Cup, ending Williams' 28-game winning streak.

Cepelova raced out to a 5-0 lead in the first set, tennis.si.com reported. Williams battled back, as she did in several of her matches at the Sony Open, to close the gap to 5-4. Cepelova, however, finally closed the set on her serve. Early in the second set, Williams called a medical timeout to have her thigh taped.

Sensing Williams' fatigue, Cepelova moved the world's No. 1 player around with drop shots and passing shots that ended the match.

"I tried, but I just couldn't do any more," Williams said, according to tennis.si.com. "Physically, I just couldn't give any more."

Williams also admitted that she knew nothing of her foe.

"She was a great counterpuncher," Williams said. "She hit a lot of balls back, and I really knew nothing about her game. So she played a really good game against me."

Tennis.si.com reported that Williams has played 149 matches since the start of the 2012 season and has 20 titles. Before she started working with her current coach and boyfriend Patrick Mouratoglou, Williams was known for playing a limited schedule.

But while Mouratoglou has helped Williams establish herself as the unquestioned No. 1 player in the world, she has started to incur more injuries to start 2014, just like Woods did last year with his back and caused him have surgery and miss The Masters.

"I'm really just dead," Williams said. "I need some weeks off where I don't think about tennis and kind of regroup. I've had a long couple of years, and I'm really a little fatigued.

"I just think I've been training really hard and putting so much effort into every day for a couple of years now. I think sometimes taking a break is just can as important as training, and I haven't been really doing that so much."

Hopefully, Serena's camp learns from Tiger Woods' plight, and relearns to moderate her schedule.

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