Until late in the game yesterday the Cubs didn't have any offense outside of the 1st inning during the series. Saturday is basically a coin flip looking at all the high level stuff. We dominated game 1 and 2, game 3 was close and got hammered yesterday so I'm not worried more than it's one game between 2 evenly matched teams.
For me the missed opportunities I look at the 8th inning of game 3. I'm pretty confident that if we just tie the game at that point we find a way to win, because up to that point the only Cubs offense was the first inning and we still had solid arms to use if the game goes into extras, and after those first 2 games I'd imagine letting the score get tied again would be pretty deflating.