Jose Mourinho reportedly kept a stash of acorns in his coat pockets and would throw them at his Chelsea players in an attempt to boost morale.
The Portuguese manager, who was sacked by the champions on Thursday, resorted to the tactic "to inject humour" into training sessions as the Blues' bad results began to pile up this season.
"Jose often found the best way to get out of a hole was to take the heat out of the situation," a source told The Sun. "It was business as usual which meant training hard but he tried to get the message across that it wouldn't help to be so glum all the time.
"He would walk around the training ground and when no-one was watching he would pick up handfuls of acorns off the grass and stuff them in his pockets. Then someone would suddenly get hit on the head by a flying acorn. It was the same with backroom staff. They would be at their desks and then get hit by a nut, look around and there was Jose walking away laughing.
"He was just trying to lift the pressure and the heavy atmosphere."
In a statement issued on Saturday, Mourinho insisted that he would not be taking a sabbatical following his departure from Stamford Bridge amid rumours linking him to the top job at Manchester United.