A question of sports

This is really a "Can we blame the Red Sox if they lose?" question.

So, during the regular season, any given team might come up against a team that's just worse than they are. Let's call this hypothetical team the Devil Rays. Now, I don't know if the DR has a worse record because the players aren't as good, the coaching isn't good, or just because they don't work well together.

Now, it seems to me that by the time you get into the playoffs, you've weeded out all the teams with poor players or bad coaching. So, in the end, are the playoffs just due to luck? One team having a better day than another team despite the fact that they're pretty evenly matched? Or is this the point where the true skills of a team come into play and the extra little tricks make a difference?

Or, I suppose, is it some combination of the two?