Transcript for Serena Williams' Shocking Loss at US Open
Ship some to you. Did you see this last night? Serena Williams out O the U.S. Open. She was upset. She started the open smashing records. Now facing defeat. T.j. Is here. I think Serena's loss even shocked her opponent last night. Shocked her, her opponent. I'm mad. And you. Serena Williams is not the number one tennis player in the world. She lost the ranking by losing last night. She might still be the greatest athlete ever but she was not the best tennis player on the court last night. Match point. Serena must stare down. Reporter: The tennis queen Serena Williams dethroned. After double faulting on match point at the U.S. Open semifinal. Karolina pliskova is headed to the U.S. Open final as Serena makes a quick exit. Reporter: She's lost her chance at U.S. Open glory and her number one ranking. Even her opponent, karolina pliskova, was in shock at first. I don't believe it. She's a champion so it's never easy to play her. You saw it when she was down set and a break she's still fighting. Reporter: Williams was on top of the world recently named greatette athlete ever by Nike, the proud owner of six championship tree physical and last night dressed for another win donning her self-proclaimed superhero sleeves. She came out strong. But pliskova quickly proved she has the serves and the returns of a champion. Pliskova now in front. Reporter: After losing the first set, Williams limped her way into a second set tiebreaker. I have some serious left knee problems but you're thinking of other things when you should just be playing and thinking of your shots. Reporter: Pliskova ultimately won on that fatal double fault. I'm so excited to beat Serena, so right now probably America hates me because I beat both sisters, Williams. Reporter: But no hard feelings from Williams. I wasn't at 100% but I think she played well and deserved to win today. Because she did deserve to win. It was my first U.S. Open match ever. I had never been and I was so disappointed. I wanted that third match. I really wanted to see it. She's like I don't want you in that match. No, I'm not the bad luck
This transcript has been automatically generated and may not be 100% accurate.