The French Open champion fired an unreturnable serve out wide to capture the first set but fell behind 4-1 in the second as Davis raised her level.

Despite the deficit, the feisty Pole stubbornly refused to drop her first set of the tournament, winning a tense 16-shot rally to set up break points at 4-4, which she converted when Davis whacked a backhand into the net.

The top seed admitted she was not at her best during the two-hour night match on Louis Armstrong Stadium despite reeling off the match’s final five games.

“I couldn’t find my rhythm today,” Swiatek said in an on-court interview. “She played totally differently than any other player. She played very smart.

“I’m trying to enjoy every match even when I’m not playing perfectly. Just trying to go for it. Trying to find solutions in every situation.”

Next up for Swiatek is a meeting with either Germany’s Jule Niemeier or China’s Qinwen Zheng in the Round of 16 on Monday.