The Basques had taken the lead in the game at Estadio Ciudat de Valencia, but goals from Christian Lell, Vicente Iborra and Nabil El Zhar secured the three points for Juan Ignacio Martínez’s side.
“Levante were a little less difficult than we had expected,” Bielsa told reporters after the game. “But nevertheless, they won.
“We should have been able to reverse the adverse situation, but instead we failed to impose our superiority on to the scoreboard.”
The Argentine was also unhappy at the way his side, who had Aymeric Laporte sent-off in the first half, reacted after taking the lead through Aritz Aduriz.
“The defeat came as a result of the lack of leadership on our part. After we scored, we paused unnecessarily," he added.
“We went deeper in the second half and paid for it.”