If I counter my opponent's Smoke Screen with Defy, does Smoke Screen count as being played for the purposes of Darius Trifarian's ability that cares about cards played per turn?

Ruling: No, Smoke Screen does not count as being played. Cards that are countered (negated) do not resolve, and if they do not resolve, they are not counted as played.

Sequence:

• Opponent plays Smoke Screen
• You counter it with Defy
• Smoke Screen is negated and does not resolve
• Smoke Screen is not counted as played for Darius Trifarian's ability