"I don't think I'm trying too hard," said Hamilton, who is 22 points behind Rosberg in the championship.
"I went for pole. Hindsight's a wonderful thing, but I'm there to be first, nowhere else."
Hamilton spun while braking for the second corner during his final attempt and ran wide at Turn Eight on his opening lap in qualifying. He will now start the Austrian Grand Prix ninth on the grid, while Felipe Massa takes pole.