Eusebio, who has previously coached Barcelona's B team, has said that the Catalan side "have great players", but have work to do if they are to enjoy another successful campaign.
"We were superior to Barcelona in many facets of the game. We knew it was going to be very difficult but we played a complete game. We could have won although a draw against Barca is still a good result," Eusebio told Cadena SER.
"There is still a long way to go for them. They have great players, with a lot of experience and a great mentality. But they need to improve on certain aspects of the game."
Sociedad have not lost a home league game against Barcelona since 2007.