Messi reacted angrily to something said by the Roma defender during the first half of Wednesday's friendly at Camp Nou, thrusting his head towards the France international before then grabbing his opponent by the throat.
Both players were booked for their role in the altercation but there have been claims that Messi was the aggressor and should have been dismissed.
However, Mestre feels that the whole affair was much ado about nothing.
"It is what happens in football games," he told reporters on Thursday. "I think it is anecdotal and there is no reason for giving this chapter more importance.
"It happens and it will keep happening in the future. It is normal when you play football."
After Neymar had opened the scoring in Catalunya, Messi doubled Barca's advantage shortly after the Yanga-Mbiwa incident before being replaced midway through the second half.
The four-time Ballon d'Or winner is now expected to lead the European champions' attack once more, in Tuesday's Uefa Super Cup showdown with Europa League winners Sevilla.
