Goals from Patri Guijarro, Berta Bou, debuting with the first team, Oshoala and Alexia saw a 31st victory in the Iberdrola League
Regardless of the rotations, Lluís Cortés' side had absolute control of the possession throughout this match. Patri Guijarro opened the scoring with a header from a corner.
It was a special goal as it was Barça's 150th of an incredible league season. Berta Bou, on her debut with the first team, added a second before half-time.
With the defence rarely troubled, it was only a matter of time before Barça added to the score, Oshoala scoring on the hour.
Alexia made it four on the day and 153 goals in total for the season, and there was more good news for the blaugranes with another debut, this time from María Pérez.
Barça's next match is against Sporting de Huelva at the Johan Cruyff stadium on Thursday 24 June at 4.00pm CEST.
Athletic Club, 0 Barça,4
Athletic Club: Amaia Peña, Oihane Hernández, Gimbert, Murua, Moraza, Cerro (Paula Arana, min. 80), Oihane Valdezate, Istillart (Oguiza, min. 69), Ane Azcona (Ibañez, min. 80), Lucía García (Landaluze, min. 55) and María Díaz (Eunate, min. 69) Barça: Gemma Font, Jana Fernández (Melanie, min. 72), Berta Bou, Mapi, Emma Ramírez (Ari Mingueza, min. 64), Patri (Maria Pérez, min. 72), Hamraoui (Alexia, min. 46), Cronogorcevic, Oshoala, Mariona and Jennifer Hermoso (Hansen, min. 64)