The phenomenon allowed Gabriel Paletta's back-pass to bounce over his foot and into the Milan goal.
“I am sorry for the team and fans that we didn't win, but hopefully this experience will help me to learn and get better," Donnarumma told Milan TV.
“I gave my all, unfortunately these things can happen and I keep my head up high, taking it on the chin.
“Pescara were well set out today and we struggled to react, but had chances to win it and were also a little unlucky at the end.
“The squad is ready, we go forward together and think of the next match. It's a mistake to react to this draw with anger. I keep a smile on my face and won't let my head drop after this error."