On January 28, 2018, at the Royal Rumble, Asuka won the first women's Royal Rumble match, entering at number 25 and eliminating her former rival Ember Moon and lastly Nikki Bella to earn herself a women's championship match at WrestleMania 34. Throughout January and February, Asuka started a feud with Nia Jax, who attacked her during and before her matches and wanted her title opportunity at Wrestlemania. Asuka defeated Nia Jax on February 25 at Elimination Chamber and again on the March 5 episode of "Raw". In parallel, she also took a part of the Mixed Match Challenge tournament, with The Miz as her partner in support of the charity Rescue Dogs Rock. With wins over Carmella and Big E, Sasha Banks and Finn Bálor, Alexa Bliss and Braun Strowman and finally Charlotte Flair and Bobby Roode, they won the tournament. After Flair retained the SmackDown Women's Championship against Ruby Riott on March 11 at Fastlane, Asuka challenged Charlotte for the SmackDown Women's Championship at WrestleMania 34. At the event on April 8, Asuka submitted to Charlotte, ending her WWE undefeated streak at 914 days, or roughly 2 and a half years.