I wouldn't say it's random, but luck certainly plays a big part in any short series, and you have to win 5 of them to win a TOC. In addition to good fortune, you need to rely on strategy and matchups. I've only won twice, and in one of them fatigue was such a problem that I tanked G1 of the finals to give my guys some extra rest. Put us in a hole, but I had rested SP the rest of the way and won it in 7. Anything you can do to give yourself an edge is fair game in my opinion (and crimsonblue, whoever whined at you about starting a low-IP ace needs to be slapped.)
There are many reasons fatigue is more of a challenge in TOCs than in a normal WIS season. Here are two:
-- Unlike early regular season games, there is no "damping", so if you have an extra-inning game early in the TOC, or an offensive explosion, your guys will take a major fatigue hit
-- Unlike postseason WIS, you only get extra rest between rounds if you win your series in fewer games than your next opponent won his. If you both sweep, neither of you gets extra rest (I am 99% sure of this - please someone correct me if this is erroneous)
I've done very poorly in TOCs over the years, so I'll refrain from giving any other advice. There are many owners who have been much more successful at it.