Dundee boss Jim Duffy has told Lee Wilkie that he must accept criticism - and responsibility - if he is to prove himself a top-class defender.
Lee Wilkie was substituted after 69 minutes at Celtic Park
Wilkie was the main culprit as Celtic swept Dundee aside 6-2 to return to the top of the Scottish Premier League.
His nightmare, which followed a similarly poor show against Rangers earlier in the month, led to his substitution after 69 minutes at Celtic Park.
Wilkie was booed every time he touched the ball, Celtic fans obviously taking personal exception to his performance against their title rivals.
The pressure got to the Scotland international as he gave the ball away for Celtic's fourth goal while trying to to dribble out of defence then delivered a poor pass that led to the fifth.
And Duffy said: "In the first half, I thought he did okay, but Lee is the kind of guy who seems to switch off at times.
"He has got to alleviate those lapses if he wants to be a good player.
I was worried that he might do something silly and get himself sent off
"You have to accept criticism and, if you make mistakes, you have to hold your hand up and admit your mistakes.
"You have to show strength of character."
Duffy admitted that he was in a dilemma about how substituting the player would affect the 23-year-old's confidence.
"But he is the same as anyone if they are not playing well," he said.
"In the end, I was worried that he might do something silly and get himself sent off."
Duffy was not too disheartened with the team performance, despite the scoreline.
"I thought Khizanishvili in the first half did really well and Gavin Rae played well, while Steven Milne worked really hard," he said.
Dundee's defence were all at sea after Henrik Larsson's opener
"If you are creating four or five chances on top of scoring two goals at Celtic Park then that's okay.
"But our defending was absolutely shocking.
"If you give people basic instuctions and they don't follow basic instructions, you either put it down to inexperience or find players who do follow instructions.
"Hopefully it has given them a kick up the backside, but we shall see on 31 May."