Although my heart won't disagree with you - and neither will my head, to some degree - the problem is, in any one game, almost any team can look like a Cup contender. I don't think the Leafs skaters have played well enough, outside of a handful of games this playoffs, to put themselves into a league with TBay or SJ, say.
However, I think that every team still alive has a *shot* at the Cup. The Leafs have proven, first by beating Ottawa, then by starting to come back in this series, that they belong where they are. If the rest of the team can continue to bridge the gap between their play and Belfour's, they certainly are contenders. (I'll stick with my original call of Leafs in six, in this series - although it's looking shaky now.)
We shouldn't assign too much importance to single game results. That having been said, the Leafs took a big step last night.