Celtic chairman Brian Quinn insists the relationship between his manager Gordon Strachan and Manchester United boss Sir Alex Ferguson is "pretty stable".
Neither were complimentary about each other in their autobiographies but Quinn played down talk of a feud prior to Wednesday's Champions League clash.
"Man Utd came up in the summer to play. Both men made a point of getting together," he told BBC Radio Five Live.
"The relationship between the two is pretty stable at the moment."
Meanwhile, Tommy Docherty believes Celtic may face a "drubbing" by United.
"I do think the best Celtic can get is a draw"
Docherty, who played for Celtic and is a former boss of United, told BBC Radio Scotland: "Man for man I have looked at both sides and United look very strong.
"I think United will more than edge it and Celtic could face a drubbing, although I hope they don't.
"However, who comes out on top will be decided over two matches."
Former Celtic boss Martin O'Neill has warned Manchester United that they should not underestimate their Scottish rivals.
"Celtic will be the underdogs but that doesn't bother anyone on European evenings," said O'Neill.
"There is always a feeling of real togetherness about the club and the supporters. They will be more than ready for the occasion."
Former Scotland coach Craig Brown agrees with O'Neill.
"My heart says Celtic can do something and my head says Strachan's team will have good shape," he told BBC Radio Five Live. "I don't forsee a drubbing."