Gerard Pique recognised that Barcelona played poorly against Real Valladolid as they won 1-0 at Camp Nou on Saturday.
"We didn't play well. It wasn't a good performance, not at all. The only good news is the victory," he said.
The defender added Barça needed "to get back to winning ways after two draws in La Liga" but insisted that "we have to improve because the sensations weren't good."
Barça now face Lyon in the Champions League on Tuesday and Pique says they "will havee to be better if not we will struggle."
Pique didn't look for excuses: "The opposition are also playing but I think it's more to do with us being more fluid and playing better. We need to be quicker, have more possession and from there create cahnces. If not, we become a weaker team. Other teams know that and we know it."
Messi's winning goal came from a penalty which was won by Pique at the end of the first half.
"I was clipped from behind and it destabilised me -- it's a penalty," the centre-back said.