Johan Mjallby insists Celtic boss Neil Lennon is still in a "good mood" despite the most recent threats to his security.
Lennon was targeted by two separate parcels while Paul McBride QC, who represented the Irishman in his recent disciplinary dealings with the Scottish Football Association, and MSP Trish Godman, a Celtic supporter, had one addressed to each of them. Strathclyde Police revealed the packages were "designed to cause real harm to the person who opened them".
But Hoops assistant manager Mjallby believes Lennon is taking it all in his stride and he said: "He is still the same guy. He has a lot on his plate and it's a shame that it's happened but I haven't really seen a change in him."
He added: "He is in a good mood. Sure, it has been hard for him but he is a strong character and very good at making sure that the players are the main thing."
Tensions are sure to run higher than normal when Celtic travel to Ibrox on Sunday looking for the win that will see them leapfrog Old Firm rivals Rangers at the top of the Clydesdale Bank Premier League.
SPL chief executive Neil Doncaster is hoping that the fixture passes off without any trouble.
He said: "We are distressed and concerned by the developments reported recently which are now, quite rightly, the subject of a major criminal investigation.
"Such things have no place in football; indeed they have no place in any civilised society. Football is a game which should be enjoyed safely by all.
"The eyes of not just Scotland or Britain will be on Glasgow this weekend; the Old Firm derby will be watched throughout the world.
"We hope that the fans of both Celtic and Rangers join in making the biggest football match in Britain this weekend one that is remembered for excitement on the park and for passions safely enjoyed and expressed off of it."