The Allies were doing great in the Pacific with India recaptured and the Money Islands liberated. Unfortunately Egypt had fallen and the dwindling forces in Moscow were surrounded by Germans.
The Japanese opened the attack on Moscow with a kamikaze air strike that should have strafed off enough soldiers to make it completely undefendable against Hitler’s ground forces. Snake eyes. Lots of snake eyes. A row of snake eyes from AA guns obliterated most of the Japanese attacks before they could even attack. The survivors mostly missed. About 12 Russian troops should have been lost, but instead only 2 were killed in this suicidal raid.
Still, Hitler had a 99% chance of conquering Moscow and winning the game the following round. Again, dice saved the Allies. The Axis forces had awful luck, and Moscow remained above with just one defender preventing capture.
Soon after, the Allies steamrolled into France, liberated Paris, and moved on into Berlin. Game over.
Oh, I just noticed you wanted to know about my biggest comeback, not defeat.