If the Lakers had won your sentence would have been quite the opposite.
Yes it would change, not because I was being biased or anything, but because Miami = Defending Champions. They are supposed to be the team that can beat anyone, considering that they are they have the same roster from last year, in fact, they improved their roster with Rashad Lewis and Ray Allen. They really have nothing to prove at this point in the season. The Lakers, however, have a lot to prove this season, because they have almost a brand new team, and they are struggling right now, and so are even writing them off to even make the playoffs. If they were to beat Miami (once again, the defending champions), then that would be the biggest win of the season for us, because it would be a statement game, that says "hey, we can hang with the most elite team in the NBA".
Of course I would say this was the best win of the season if we won.