The Spanish champions suffered their first home defeat of the season at the weekend as Valencia collected all three points with a 3-2 win.
"We feel like we're playing away from home. But losing makes you stronger. We have a great team that has proven itself beyond all doubt," he told Marca.
"We're not worried about the team. When you get used to winning and then you lose, it can feel like the end of the world, but people shouldn't doubt Barca.
"[Saturday's loss] wasn't a complacency issue - if we had controlled the situation better and been less predictable, maybe we'd have scored more goals."
"Now we have to pick ourselves up - there is no time to feel sorry for ourselves. We have to be mature and learn from this to stop it happening again. We have to aim to dictate the game throughout, not just for a stretch."
Barcelona sit three points behind leaders Atletico Madrid in La Liga.