France's Alizé Cornet won 6-4, 6-2 in 37 consecutive victories at Iga Sifion in the third round at Wimbledon on Saturday.
It was Swiatek's first loss since February. Poland's No. 1 in the world made 33 unforced errors and saved only one of six breakpoints against an unseeded cornet.
Swiatek's winning streak was the longest match in 25 years on the WTA Tour, marking the 1997 Martina Hingis match. Steffi Graf won 66 games in a row from 1989 to 1990.
Cornet has played in 62 consecutive Grand Slams dating back to 2007 and has advanced to Round 16 at the All England Club for the first time since 2014. She defeated the best Serena in the world at the time, Williams, 1-6, 6-3, 6-4 in the third round of the year.
"I have no words right now," Cornet said. "I remember when I defeated Serena on the same court. (No. 1) I think the court is a lucky attraction for me.
" This kind of match is what I am alive. I think. I knew I could do it. Somehow I had this belief. If I had time to beat her, I thought it was now. "
Cornet, 32, finished in a 93-minute match with 7 forced errors and 16 winners. Her next opponent is Australia's Ajla Tomljanovich, who defeated the Czech Republic's 13th Barbora Kletikova 2-6, 6-4, 6-3 on Saturday.
Spain's fourth-seeded Paula Badosa also recorded a 7-5, 7-6 (4) victory over the Czech Republic's 25th-seeded Petra Kvitova.
But the eight-seeded Jessica Pegra wasn't very lucky. Croatia's Petra Martic has finished an American run at Wimbledon, thanks to the 6-2, 7-6 (5) decision.
Amanda Anisimova, seeded in 20th place, overcame the defeat of the first set, 6-7 (4), 6-2, against 11-seeded Coco Gauff. I won 6-1. ..
"It's my first time playing on the center court. I think it's the most special day of my career," Anisimova said in an interview on the court. "Playing on this court is a great privilege ... I play Coco. She is a great player and played in the Grand Slam finals. Before the match, whether you win or lose, prepare to immerse yourself in this moment. Today's victory is very special. "
Anisimova will face the unseeded French woman Harmony Tan. Harmony Tan defeated Katie Ballter in England 6-1 and 6-1.
Romanian Simona Halep defeated Poland's Magdalena Fletch 6-4, 6-1 and Kazakhstan's 17-seeded Elena Rybakina struggled before 7-6. (4), she beat China's Qinwen Zheng 7-5.
– Field-level media