SFA president George Peat hit back, questioning the courage of the unknown Celtic source, but there is little doubt that the pressure has increased on 44-year-old McDonald.
Tony Mowbray's side are seven points behind Rangers at the top of the SPL having played a game more.
McDonald, in Spain for a referees' winter training camp, told www.scottishfa.co.uk: "You are aware that it is the biggest game in the country and that one team is always trying to catch the other.
"The television coverage is much greater but you have the added aspect of phone-ins, websites and other media outlets.
"It is a constant feeding frenzy but, as Ally McCoist said recently, the actual refereeing and decision making hasn't changed that much, it is the exposure that is far greater.
"The important thing for all referees is not to take the criticism to heart.
"That was a theme of the training camp.
"It is always important to reflect on your performances and be mindful of the extra scrutiny on televised matches.
"You would be a fool not to learn from all experiences, whether good or bad."