The Blues took far fewer shots on goal than San Jose, but made the most of their opportunities. Their three goals were part of only eight shots on goal in the third period, and only 20 shots on goal overall. St. Louis goaltender Brian Elliott picked up the win while blocking 34 of 36 shots. By contrast, Greiss saved just 16 of 20 chances.
The season has only just gotten underway, so it's far too early for San Jose to start getting nervous about Greiss. This game was much more about St. Louis taking advantage of every opportunity they had, and the Sharks failing to capitalize when on offense. Brent Burns and Michal Handzus picked up San Jose's goals.
You can discuss the game in infinitesimal detail over at Fear The Fin.