Iga Swiatek may be the world number one and have had a 37-match winning streak this year but says she is surprised to reach this week's US Open semi-finals.
Swiatek qualified for her third grand slam semi-final for the season with a 6-3 7-6 (7-4) victory over American eighth seed Jessica Pegula in one hour and 53 minutes on Wednesday.
The 2022 French Open champion and 2022 Australian Open semi-finalist became the first women's top seed to reach the last four at Flushing Meadows since Serena Williams in 2016.
The victory comes after Swiatek's 37-match winning streak was ended in the third round at Wimbledon in June by Alize Cornet, winning four out of seven matches at three tournaments following that as the WTA Tour moved to hard courts in the lead-up to the US Open.
Swiatek expressed her surprise at making the last four during her on-court interview after the match and explained that, following early losses in the lead-up tournaments in Cincinnati and Toronto.
"Looking logically at the last tournaments, I just didn't know if this one is going to be possible for me to be consistent and to win so many matches in a row," Swiatek told reporters.
"I feel like I've been playing better and better every week since the start of this swing. So it surprised me because after the losses that I had in Toronto and Cincinnati, I just wasn't expecting to play so well here.
"It gave me actually a lot because I could be kind of an underdog again, not maybe fully, but just not expect from myself that I'm going to win everything right now."
The Pole said her game "clicked" against Pegula, hitting 22 winners compared to the American's 14, winning 43-of-71 points on return.
"I'm pretty proud of it because I feel like I'm playing better and better every match," she said.
"Jessie was a tough opponent today, for sure. Second set was really tight. We both were fighting till the last point. I'm proud of myself that I could be the one to win the last one."
Swiatek will take on Aryna Sabalenka in the semi-finals, while Pegula bows out having reached the quarter-finals at three of the four majors this year.
"I go back and forth, I should be positive," Pegula said. "At the same time I'm like, three quarterfinals. Sorry, but it sucks. It sucks.
"I wish I could have done it here at my home slam, but I guess not. I wish I didn't have to play Iga every quarter-final or Ash Barty, which seem to be the two people that don't really lose that often. So it just sucks.
"I had a great year at the slams. I know there's still some tournaments left. I'm a little deflated right now. I'm not real happy. It just sucks to lose. I just wish it would have been different tonight."