The Basques' coach has reached the end of his tether regarding recent poor performances and has demanded some sort of reaction from his players.
"Too many times we've been in this situation," he told reporters at a press conference. "We will have to start over.
"We were just never able to follow up in a positive way. We could not exploit the good positions we found ourselves in.
"We lacked any sort of depth and just weren't dangerous enough in attack."
Goals from Helder Postiga and Apono ensured Bielsa’s side suffered their latest defeat at San Mames, leaving Athletic in 13th place in La Liga.