A comment kindly nudged me in the direction of Fangraphs.com, an already good site which has now become indispensable by producing win expectancy charts for every game. Basically, these show the progress of a game through every out: initially, a team has a 50% chance of winning, but every hit increases the change, and every out decreases it, (some a lot more than others, obviously), until the end, when one team hits 100%. It's a very neat way to track any contest - here's the graph for last night:
It was, as you can see, the homer, double, triple, balk sequence in the fourth inning that really turned this around, changing our chances of victory from about 40%, to around 85%. Gonzalez had the most positive effect on our chances, as +21.4% - I guess that includes the balk, which is somewhat doubtful, though the methodology means someone has to get credit for everything. But if you want to see a real switchback, look at the chart for Monday's 10-9 defeat...