Gordon Strachan has told Neil Lennon to turn his full backs into wingers and follow the Liverpool blueprint for a back four.
The former Hoops boss was surprised to hear Lennon's reasoning for continuing with the 3-5-2 against AC Milan despite the disappointing showing against Rangers on Saturday.
Celtic have just Moi Elyounoussi as a recognised first team winger and put Ryan Christie wide on the right after changing shape at half time in the 3-1 defeat to Milan.
Lennon insisted he didn't have the options to start with a back four despite the improved second half performance.
But Strachan has urged him to go with what he has and use Jeremie Frimpong and Diego Laxalt as attacking full backs in the mould of Liverpool.
Jurgen Klopp plays with Trent Alexander-Arnold and Andy Robertson in advanced roles with Sadio Mane and Mo Salah often cutting inside from their initial wide position.
And Strachan told BT Sport: "He mentioned playing a back four that he's not got widemen.
"I think if you have a look at Liverpool their widemen are their full-backs in a back four and all they need is maybe a sitting midfield player in front of the two centre-backs and I think that's the way he will get on with it.
"I know that Celtic Football Club and Neil likes to play with wingers but if you have not got them just now you could say to Frimpong and Laxalt to go on a little bit and say to the midfield player to sit in.
"It would be like three centre halves but one is in front.
"I think after tonight they will feel a lot better about themselves at training tomorrow and you need that going to Aberdeen."
