John Kennedy, the Celtic first-team coach, has made a case for the club’s defence in the wake of their UEFA Champions League exit on Tuesday evening.

Ronny Deila’s side have been heavily criticised for their use of a zonal marking system after losing 4-3 on aggregate to Swedish champions Malmo. Three of the four goals came from set-pieces, but Kennedy has maintained that there will be no knee-jerk reaction to dump a system which he maintains is the best use of the resources which Celtic have available to them.

In European competition since Deila took over from former manager Neil Lennon, Celtic have shipped 28 goals in 21 games. The imminent departure of Virgil van Dijk will compound Celtic’s defensive headaches and while the Europa League is little more than a consolation prize for the Parkhead side this season they will go into it still convinced of the merits of the zonal system.

"When you concede from zonal marking this debate always comes up,” said Kennedy."When you concede from man marking nobody bats an eyelid. We have worked on zonal marking and we firmly believe in it and the players we have at the club are suited to that style of play.

"In one game it has not worked for us. Over the course of last season I think we conceded just two goals from set plays domestically. We have managed to concede three over two ties in the Champions League which is very disappointing.I am a large part of that and I will take responsibility for the set plays a lot of time and I will shoulder the blame for it.

"There was a number of factors that led to the goals and why we did not perform well enough and as a group and a unit we need to take responsibility for that and understand what went wrong so that when it comes to this time again we are better prepared for it.

“When you man-mark, whoever Virgil van Dijk is marking, you can take him out to the back area where it is not a danger and all of a sudden you leave your goal quite isolated. So we tend to put our bigger guys in areas we feel are most dangerous. It has worked for us in the past. It has not quite worked for us this time but it is not solely down to zonal marking. You look at the whole performance which ultimately wasn’t good enough.”

However, former Celtic and Republic of Ireland goalkeeper Pat Bonner is uncomfortable with the reliance on the zonal system and would rather there was also an inclusion of more traditional defensive methods.

“I would prefer a mix of zonal and man marking and the guys who are not the main headers of the ball still have a job to do,” said the Irishman. “At the first goal [on Tuesday night], they had eight bodies in the six yard box and for the second, they had seven in there. Too many bodies.

“You come up with a strategy and their way of doing it is zonal. It has worked in the past to a degree and they’ve gone with it in this European game but Malmo had their homework done.

“When you allow people to get a run on you, even over only four or five yards, then you are going to be out-jumped and that’s what happened at both goals. Their total zonal marking, when analysed, it didn’t work. If I was the opposition playing against that, I would do what they did and block them off. Then if the delivery is right, you’ve got a chance.”

Kennedy was speaking at Hampden as Celtic were paired with Raith Rovers in the third round of the League Cup.