To start with the elephant in the room, I don't actually think Mike Matheny is to blame for this loss. Most people do. But a lot of things happened that he can't really control. I think he made one mistake, but it's mostly hindsight. For the most part the bullpen completely and utterly let the team down and you can't really do much about that.
The Reds got on the board first. Adam Wainwright walked Billy Hamilton on 10 pitches to begin the game. Hamilton was 0-7 with 7 strikeouts and one walk against Wainwright so he was probably in full-on "I just don't want to strike out" mode.