Barca lost ground on the leaders after the 3-1 loss.
"We're still one win off the top and it's nothing to be worried about. It wasn't our day. Real Sociedad is a team that plays good football," said Pique.
The 'Azulgranas' centre-back admitted his side failed to boss the encounter: "We didn't feel comfortable. We weren't able to keep possession, which is our forte, and that allowed them to create chances."