Overwatch league - Draws in playoffs
If it comes to a 2-2 situation in a playoff match, a 6th map will be played.
It was mentioned in the live stream of that very match by Semmler, starting at about 30s in the VOD.
Season 1, Stage 3 Playoffs, NYX-BOS: https://overwatchleague.com/en-en/match/10545/game/10297