Despite the gulf in the table between the sides, it was third-bottom Real Valladolid who emerged victorious on the day thanks to Fausto Rossi's first-half strike.
Barca have now lost three of their last six matches in La Liga and have dropped to third as a result, a point behind the top two of Real and Atletico Madrid, with Carlo Ancelotti's men still to play this weekend.
And although Martino has not given up on retaining their league crown, he knows his side must find some form before their March 23 meeting with leaders Real at the Bernabeu.
"The team lacked ideas against Valladolid but not intensity," he said on www.fcbarcelona.com.
"We completely failed in generating play and that's what stopped us from getting the result.
"We lacked what makes us Barca: good elaboration in our build-up, finding spaces, breaking through on the wings and having depth. But we didn't lack attitude.
"We had very few chances of actually running at goal. We almost always had to fight against 10 defenders. A good solution would have been creating more space.
"Our obligation is to fight for La Liga until the last moment and that's what we're going to do. We have to win at the Bernabeu regardless.
"Currently we aren't at our best and we have to find our best form in order to play against teams like Real Madrid. We have 15 days to do it."
Barca will aim to defend their 2-0 lead over Manchester City in the Champions League last 16 on Tuesday before taking on Osasuna in the league ahead of the Real showdown.