Despite having one eye on the UEFA Champions League midweek, Ernesto Valveder went with Lionel Messi, Luis Suarez and Antoine Griezmann, while Gerard Pique and Ousmane Dembele missed were suspended.
It was the Catalan giants who broke through after just 13 mnutes as Clement Lenglet's long ball released Griezmann, who calmly slotted past Marko Dmitrovic.
Messi netted his first goal of the season in the 4-0 win over Sevilla before the FIFA break, and he nearly got a second on 30 minute but Dmitrovic showed good work to deny the Argentine a certain goal with the net gaping.
At the other end though, Eibar barely provided any real threat to Marc-Andre Ter Stegen's goal, much to the disappointment of the home supporters.
Barca picked up from where they left off in the second half as Messi doubled his side's lead in the 58th minute after collecting a pass from Griezmann before calmly slotting home.
Eight minutes later, the front three combined to good effect with Griezmann playing in Messi who unselfishly teed up Suarez for the simple finish to make it 3-0.
The third goal seemingly dashed any hopes for the home side, who continued to struggle in the final third as the Catalan giants ran out convicing winners on the day to move top for a few hours at least.