The Celtic boss said: "It's poor. We started okay then got really ragged with the ball. Our passing, technique, just got really ragged.

"I keep saying if we don't defend set plays properly we'll get punished and that is exactly what happened

"There's a lack of application. Don't know where it's come from because we had a good week, a good day on Sunday (2-0 William Hill Scottish Cup semi-final win over Aberdeen).

"Lack of hunger was really apparent. The hungrier team won and that's on us.

"I can't defend the players. I've tried to over the piece but I can't tonight."

Lennon agreed with midfielder Callum McGregor's description of the defeat as embarrassing.

The Northern Irishman said: "Of course it is. It's unacceptable. A lack of application, lack of hunger.

"There has to be a culture change. I have to change it quickly and the players have to change quickly because it's not acceptable.

"I need to get them more hungry, more on point, back to basics. We didn't do basics well enough, didn't use our bodies, didn't run. All the things that Sparta did.

"We need to be far more aggressive as individuals. As a manager I have to accept responsibility but players need to look at themselves as individuals.

"We got back into it at 2-1 and looked like we showed character but the third goal is too easy.

"We need to get back to showing a bit more humility, working hard on the training ground.

"I didn't see that coming after Sunday, a great performance, four-day break.

"We didn't do the basics well enough. A set play, they've hardly been in our half.

"A corner isn't even that well hit. But we should be there for first contact, be more aggressive with defending. We bang the drum about that all the time."