Barcelona failed to beat Levante on Sunday, relying on Gerard Pique's equaliser to take a share of the spoils in Madrid and the Argentine believes the title race will be close
The home side took the lead in Valencia through Loukas Vyntra's strike on 10 minutes, but Gerard Pique's equaliser, nine minutes later, ensured the Blaugrana came away with a point.
The result means the reigning Liga champions remain top of the division on goal difference after second-placed Atletico Madrid missed the chance to overtake, drawing 1-1 with Sevilla on Sunday evening - with Martino acknowledging just how tight it is at the top.
"The championship will be very tight. There are 18 dates remaining and there will be more surprises," the 51-year-old said after the game.
"We cannot blame anything. We did not deserve this outcome, we were unlucky not to win. The Levante goalkeeper had a great game."
Cesc Fabregas reacted angrily after being replaced by Sergi Roberto in the second half of the contest, but Martino insisted he understands the emotions felt by the Spain midfielder.
"I can imagine that he was disappointed, it is understandable because he wanted to play the full game."