Dee ihe ga-aga n'ihu na paragraf a - N'afọ 2015, Serena Williams kpebiri ịmalite oge ya na ihe ngosi ngosi na Perth, na Hopman Cup
na-esonyere John Isner, na-efunahụ na njedebe nke ndị Poland Agnieszka Radwańska na Jerzy Janowicz. Na Australian Open, Williams kwuru na ya 19 slam merie Maria Sharapova, na-etinye ya 2nd na ọtụtụ slams meriri na Open Era. Williams kwụsịrị afọ iri na anọ ya na BNP Paribas Open mana ọ lara ezumike nká tupu egwuregwu ọkara ikpeazụ ya. O mechara nweta aha nke asatọ ya na Miami Open na-emeri Carla Suárez Navarro na naanị nkeji iri ise na ise na nke ikpeazụ mgbe o meriri Simona Halep siri ike nke atọ. Mgbe ahụ, ọ ruru asọmpi ikpeazụ nke French Open wee kwuo na ọ bụ slam nke 20 ya meriri Lucie Šafářová na atọ atọ, na-eme ka ọ bụrụ naanị onye nke abụọ iji merie slam ọ bụla ugboro atọ. Ọ kwadoro ya site na mmeri ya nke isii Wimbledon megide Garbiñe Muguruza iji bụrụ onye mbụ meriri slam atọ ugboro isii na onye ọkpụkpọ mbụ kemgbe Steffi Graf iji merie slam atọ mbụ nke afọ. Williams lọtara site na mmerụ ahụ ikpere na Toronto mana ọ tụrụ onye Switzerland na-eto eto Belinda Bencic na ọkara ikpeazu. O mechara nweta aha nke ise ya n'afọ ahụ na Western & Southern Open na-emeri Simona Halep. Na US Open, Williams nwere ohere iji merie Grand Slam kalenda mana Roberta Vinci kpasuru ya iwe na setị atọ na ọkara ikpeazu. Williams bụ onye mmeri na-agbachitere ugboro atọ, mana na Ọktọba 2, Williams wepụrụ na asọmpi ahụ iji gwọọ mmerụ ahụ ya ma nwetaghachi mkpali ya.