The way miami was playing first game looked like it could have been a similar result except instead of getting net the guys no names james were getting intimate nailing the rim. Game three could very well be do or die for the spurs.
The game three winner in the 2-3-2 series after coming in 1-1 is 12-1 overall in the Finals. The only team to lose in that situation was the Heat in 2011.
As for the comment earlier about the Heat not being able to play at that level again, you haven't watched the Heat much this year. The only thing that was a little bit of an outlier was their lack of turnovers, but it wasn't a crazy outlier like SA's lack of turnovers in game one.
Duncan has put up great per 36 minute numbers, equal to his career averages, this year. But his playing time has been way down all season due to his age. They are trying to ramp up his PT in the playoffs and especially the Finals. Can he really go for 40 minutes a night? Was game two just a bad night or indicative of the problem of having him try to run the floor with the pace and space Heat? Most likely a little of both, but the Spurs can't do well unless he is the second best player on the court each night.
Ginobili has also been extremely on/off this season. He spent most of the regular season playing like Wade is playing now.
Parker seems most likely to be the guy SA leans on to carry them, as he has all season. The problem is/has always been that Parker can't defend. The difference between him and MVP vintage Steve Nash is pretty small. He can get to where he wants on the floor, is never rushed, can get shots up in traffic and nail the open shot. Also, he is a defensive liability.
The Chalmers/Lebron pick and roll that eviscerated the Spurs did so because Parker sucks as a defender. Chalmers is a competent starting PG and unless he is having an off night can exploit Parker on that end of the floor. The low screen and roll was used so SA wouldn't have time to send wing help defenders like they would on a high screen. If they were already packing the paint from the wing then the closeout to the wing would be late, and it was for those open Miller and Allen threes.
What does SA do about it? Pressure the ball before it gets to the painted area. Rely on the SA bigs to be much more aggressive about rolling over to stop the basket attack and hope Bosh or Haslem aren't nailed the wide open 18 footers that will come out of that. (Just read somewhere that the Heat have won the last 30something games where Bosh shoots better than 50% - this is why). The wing defenders don't have to stay home necessarily, but they can't cheat in as far as they have and what cheating they do has to stay in passing lanes. Maybe they can get away with moving Parker to guard a Heat wing shooter but transition matchups can create a problem.
So if the Spurs defend the play perfectly, given their personnel, we will see tons of midrange jumpers for the Miami big. With the wing defenders at home the Spurs will continue to give up the rebounding edge to Miami. But if they are proactive instead of reactive they will have to start pressing and trapping the ball. They need to run a deeper bench and throw bodies who will press the ball the length of the court, slow possessions and wear down the Heat as much as possible and hope for turnovers. SA hasn't been know for being a tough defensive team in years but they will have to do something to slow the Heat attack.
On offense the Spurs have sputtered both games. In game one they struggled to score despite a record low number of turnovers. In game two they struggled to score despite an incredible three point shooting barrage. If they revert to the norm on turnovers and threes in the same game it will be uglier than the last game. They need to be in the paint more and get more out of the "mismatch" of having Duncan and Splitter. If they are gonna play big they are going to have to exploit it on the offensive end of the floor. If not, roll out small ball and get everyone driving into the paint. Especially at home!