Barcelona forward Antoine Griezmann believes his side were unable to react to Levante's second half onslaught, as they lost 3-1 at the Ciutat de Valencia.
Lionel Messi put the defending La Liga champions ahead from the penalty spot in the first half, however goals from Jose Campana, Borja Mayoral and Nemanja Radoja secure a dramatic turnaround for the hosts.
Barcelona shell shocked by the rapid response of their hosts, and were unable to muster up a reaction of their own, much to the frustration of Griezmann.
"We lacked some concentration in the second half,
"After they scored their goals, we did not know how to react.
"We were not at 100% today, and they were better than us.
"It is difficult to know what the issue was, but today, we did not perform."
Griezmann returned to the side after being left out of the team that won 5-1 at home to Real Valladolid in league action in midweek, but he added that he is not concerned about his place in the team.
Barcelona now face Czech side Slavia Prague in the Champions League in midweek, where a win will put them into the quarter finals, with Inter Milan taking Borussia Dortmund.