Martin O'Neill has hinted Celtic could change their shape after two crushing defeats.
Despite a bright start against Ferencvaros, it was another insipid 90 minutes on the whole, days after losing to Rangers in the Premier Sports Cup. Across the two games, it is six goals conceded and could have been more.
Celtic have played with a 4-3-3 formation for a number of years but O'Neill has hinted it could be time for a change, having struggled in midfield in recent weeks and been vulnerable to counter attacks.
Asked if he is still figuring out the best formula after signing a raft of new players, the manager said: "Yeah, of course.
"Yeah, and I think that will take a little bit of time because the football club here has been used to 4-3-3 for quite some considerable time, for quite a number of years as well.
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"And I think that if we're going to try and get the best out of our best players, then we're going to have to find another way.
"We went 4-4-2 in the second half. Of course, sometimes that deprives you for the extra player in the middle of the field. But it was worth risking because we wanted to do that. And I take responsibility for that."
Meanwhile, the 74-year-old responded to the boos that rung around Parkhead during and after last night's game.
"You know, I've been here 25 years ago where the crowd can react like that there. So it's genuinely nothing new to me at the end of it all.
"I think that they were showing a lot of frustration as well too. At times when we had the ball, we looked as if we were going forward, the next thing you know, we put two passes backwards.
"So those things definitely frustrate you. And that's something we'll have to try and iron out," he said.