Neil Lennon is looking for an "instant reaction" from his players in Tuesday night's Scottish Communities League Cup quarter-final game against St Johnstone following Celtic's historic 2-0 home defeat to Kilmarnock yesterday.
Former Celt Cillian Sheridan scored two minutes before the break and midfielder Liam Kelly slammed in the second from the spot just after the hour mark to register Killie's first victory in the east end of Glasgow for a remarkable 57 years.
"It was as poor as we have played under my tenureship here and I will be looking for an instant reaction on Tuesday," said the Parkhead boss. "You think that after the while they will find their feet and work their way into the game."
The Hoops' lacklustre performance was all the more puzzling given their disciplined, battling display against Barcelona in the Nou Camp in midweek where they only lost the Champions League clash 2-1 to a Jordi Alba goal in the final seconds of injury-time.
Celtic remain top of the Clydesdale Bank Premier League but Lennon described his side's performance against Kilmarnock as "unacceptable" and is looking for a big improvement for the visit of the Perth men.
Lennon added: "There were too many touches on the ball and I think the two centre halves of Kilmarnock had one of their easiest games of the season and that is very disappointing.
"I don't remember us working their keeper in the first-half, we had good chances in the second-half but not enough as far as I'm concerned.
"There were times we were passing for the sake of passing and I want better. I want players to push each other on but I didn't see enough of that."