Former Celtic striker John Hartson has told The Scottish Sun that the Bhoys' defending from set piece simply isn't good enough - and has cost the club millions of pounds.
Celtic bounced back from two successive draws against Hearts and Fenerbahce by beating Hamilton Academical this afternoon - but they had to work extremely hard for their win.
Goals from Dedryck Boyata and Leigh Griffiths gave Celtic a 2-1 win, having cancelled out Gramoz Kurtaj's opener at New Douglas Park.
It was a much-needed victory for Bhoys manager Ronny Deila, who has been under pressure from sections of the Celtic fanbase in recent weeks.
Whilst his side are seemingly back on track, former Celtic striker John Hartson believes there is one big problem in the team holding them back right now.
Speaking to The Scottish Sun, Hartson claims that Celtic's defending from set pieces isn't good enough - and cost the Bhoys millions of pounds in recent months.
"Okay, they have lost Virgil van Dijk, but he was part of a defence guilty of this as well, and they’ve had to chop and change at the back too much lately," said Hartson. "But if you are a defender playing for a club like Celtic you should be good enough to handle corners and free kicks into the box. Under Martin O’Neill we played a zonal marking system and we didn’t lose many goals from set pieces.
"But this Celtic team are losing them in every big game and that’s what’s cost the club millions. If it wasn’t for losing goals at set plays, Celtic would be in the Champions League. I’m sure of it. The goal they conceded against Malmo in the final minute at Celtic Park is what did the real damage.
"That was the moment the Swedish team started to believe they could win the tie, you saw that from their celebrations. Not stopping Jo Inge Berget from grabbing that goal changed the tie. All the good work they’d done early in the game unravelled," he added.
The goal by Berget for Malmo started Celtic's set piece problems, before Markus Rosenberg scored from another corner in the second leg of their Champions League play-off, dumping the Bhoys out of the competition.
The same problem came back to haunt Celtic again on Thursday night, as Fernandao netted from a corner to hand Fenerbahce a point in their Europa League clash, highlighting the issue as arguably the biggest problem facing Deila at the moment,
New defenders such as Saidy Janko, Dedryck Boyata, Jozo Simunovic and Tyler Blackett have made it difficult for the Celtic back line to play as a consistent unit so far this season, but basic defending from set pieces has to improve if Celtic are to improve under Deila this season - and the Norwegian has to solve the problems quickly.