Karolina Muchova made a rather stark admission after reaching the third round of the 2025 US Open earlier on Wednesday (August 27). The Czech attributed a lapse in focus in the opening set of her last victory to her ex-boyfriend being amongst the crowd, which has since prompted the tennis community to ask the WTA and the USTA to intervene in the situation.11th-seeded Muchova went to three sets in her second-round affair against Romanian veteran Sorana Cirstea at this week's US Open, eking out a 7-6(0), 6-7(3), 6-4 win in just under three hours. The 29-year-old had initially fallen behind by a break in the first set of the match at Grandstand, and she has now given more context behind what contributed to that.Speaking to the media later, Karolina Muchova claimed that the presence of her ex-boyfriend, who sat quite near her players' box by her own admission, led to her losing composure against her older opponent."It wasn't tennis-related, so I don't really like talking about it. But opposite my bench, my ex-boyfriend sat down. He sometimes shows up at events where he shouldn't be," Karolina Muchova told the press in New York. "That startled me a bit. I told him to leave, he didn't, but later he did go. It was hard to focus in that moment."Although the former World No. 8 was able to regroup, many fans have criticised the man in question for potentially stalking her. One fan was pretty damning in their reaction to the news on X (formerly Twitter) as they alluded to previous cases where Iga Swiatek and Emma Raducanu were targeted by stalkers."The way women are never safe especially during such high level events is genuinely so scary. I hope @WTA take action asap because there has been too many cases like this recently... first with Emma, then Iga and now Karo," the fan insisted on X.A few others also requested the WTA and the US Open organisers to protect Muchova from spectators in the future."If it’s true she needs to tell the tournament and the WTA," one fan wrote."Get the guy banned now @WTA @usopen," another claimed."Okay woah... hey @usopen @wta can you please get more info about it, check up on karolina and ask her if she’s allowing you guys to do smth with it???" one more fan called for action.Another bunch of fans, meanwhile, were hysterical at the fact that some men pose a danger to even someone as successful as the Czech."F*** THIS GUY. this is so scary. may she be protected from all evil," one fan asserted."TF is wrong with some men?" another questioned."That’s………. actually why we should ban men... it’s that simple," one more fan claimed.Karolina Muchova will next face her countrywoman Linda Noskova for a place in the second week at Flushing Meadows. She will be eager to emulate her career-best result of reaching the semifinals of the tournament in the last two years.Taking a look at Iga Swiatek and Emma Raducanu's stalker controversies following Karolina Muchova's US Open admissionEmma Raducanu had a similar experience to that of Karolina Muchova in Dubai | Image Source: GettyKarolina Muchova's unfortunate experience at the 2025 US Open this week comes after Iga Swiatek and Emma Raducanu were stalked by male tennis fans during their tournament campaigns at this year's Miami Open and Dubai Tennis Championships, respectively. The World No. 3 became the subject of fascination of a toxic troll, who on several occasions talked about his idol and her devout fans on social media.Raducanu, on her part, was reduced to tears after an obsessed fan was in attendance during her second-round outing at the Dubai Tennis Championships, coincidentally enough, against Muchova earlier in February. The 2021 US Open champion was reduced to tears as she hid behind the umpire's chair before the spectator was eventually ejected from the crowd.It later came out that the man had been keeping tabs on the Brit and her team's schedule since the Singapore Tennis Open a few weeks prior. The situation was indeed so serious that the WTA was forced to ban the fan from attending any tour-level events, including Wimbledon in July.