The odds you beat them 3 in a row, having already beaten them 2 in a row, are excellent as compared to the odds before the series starts.
If you assume that the Brewers should win 60% of the games between the two teams, then the odds of the Nats winning tonight or any other single game in the series are 40%. Feel free to adjust the % to your liking, the math works in the same way regardless.
If you asked if the Nats could win 3 in a row before the start of the series, the odds would have been 40% to the 3rd power, or 6.4%. However, as already observed, the Nats no longer have to win 3 straight. They only have to win one.
*sigh* You'll never get through, Tom. Of course, numbers aside, there is a psychological factor, as no one likes to get swept.
But let's use the "Let's Make a Deal" issue to illustrate things:http://www.dcity.org/braingames/3doors/index.htm
There are 3 doors. Two have goats behind them, another has a brand new car.
You pick door #2. Monty Hall shows you that door #1 has a goat behind it. Should you stick with door #2 or switch two door #3?
The answer is that switching is a better bet.
Sportsfan, your homework is to figure out why