Yes. Of the three blown calls yesterday (the other two resulting in managers getting tossed in the two ALDS games), that was the only one that really had an impact on the possible outcome of the game. Posey was out. He pretty much admitted it after the game. Without that run, it's 0-0 after 9.
From ESPN....
In Thursday's National League Division Series opener between San Francisco and Atlanta, Giants catcher Buster Posey was credited with a stolen base when replays showed he appeared to be tagged out. Posey later scored the lone run in the Giants' 1-0 win over the Braves.
"I guess it's a good thing we don't have instant replay right now," Posey told reporters after the game.