A factor that really ended up manifesting itself in the last 3 games: defense and the ability to capitalize on mistakes.
The Cubs much talked about defense came through with big plays- and even when Baez made an error early in game 6, the Dodgers could not make them pay and plant an early seed of doubt. In baseball, you can't let a team off the hook when they make an error like that.
Meanwhile, LA made plenty of errors and Chicago capitalized- a bad throw on a sac fly by Baez plated TWO runs, the 8th inning of game 5 saw a couple of lousy plays on short dribblers that led to that big offensive explosion, Toles' 1st inning error set the stage for 2-0 tonight.
It was an ironic role reversal- in 2008, when these teams met in the NLDS, there was a game where every Cubs infielder made an error and LA capitalized.
This time, it was the Dodgers making the errors and Chicago capitalizing.