By Amy Tennery and Shrivathsa Sridhar NEW YORK (Reuters) -Defending U.S. Open champion Aryna Sabalenka was given an early test before she moved into the second round while Emma Raducanu won her first match at the Grand Slam since her 2021 triumph as the tournament began a day earlier than usual on Sunday.

Emma Raducanu bagged her first US Open victory since her fairytale 2021 title triumph on Sunday with a straight sets demolition of Japanese qualifier Ena Shibahara.