Karolina Pliskova acknowledges she's under pressure to perform at the US Open, being No. 1 and having reached the final in 2016.
The Czech has gone three sets in both of the previous two rounds.
"I think I'm playing in quite big waves this tournament so far. So I think sometimes I think I play good shots, good rallies, and then there is hundreds of mistakes and not a good shot," she said.