Caroline Wozniacki faces an uphill battle to stop Serena Williams reaching the semi-finals of the Olympic tennis event when they take to Court One on Thursday.
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Serena has been moving through the gears this week and she sent a message to the rest of the women's draw with a brutal display of hitting to see off former Wimbledon finalist Vera Zvonareva 6-1, 6-0 in just 51 minutes on Wednesday.
Serena smashed 32 winners and afterwards revealed she had been loving the chance to compete underneath the Centre Court roof for the first time. "Indoors, grass, it doesn't get better than this," she enthused. "Grass is a dream court, but then to play indoors on grass? Oh my God, it's crazy. I was nervous going into the match. I didn't speak to anyone. I had a bad practice. I thought, 'Gosh I'm stressed out.' But I think I played better today, and even in my second round, than any match I played at Wimbledon. I was playing unbelievable. I felt good. I was relaxed. I felt no pressure out there. I had no idea I would play like this. I was a little surprised."
Wozniacki wasn't surprised. She pulled out her best performance of the Games to defeat Daniela Hantuchova 6-4, 6-2 but she knows how tough this match is going to be for her.
"Serena is playing really well. She played unbelievable today," Wozniacki said. "You definitely have to go out and play your best tennis to beat her."
She actually stunned Serena 6-4, 6-4 at the Miami Masters in March but Serena still leads their head-to-head 4-1 and beat her in the US Open semi-finals last year.
Prediction: Serena in two.