Match was US server, by this account Pangolier#2510, ended around June.8th 2am EST. I was Elise and played Alexstraza in final 2. I won the round twice (would’ve killed them both times) but they took 0 damage both times, and game just went on for another turn; and finally when they won I just died and got 2nd place.
Nobody cheated. This is a known bug in battlegrounds that has been around for a long time.
In some situations, players become “desynced” from each other and they can see different outcomes for a battle. When this happens, each player takes the amount of damage they see on their own screen.
If he took no damage, that must mean that on his screen, he saw himself win.