How do I twist a curve (by rotating a segment)? I have already searched everywhere but those threads are about making rope-like objects.

I am trying to animate start and end values of a curve's geometry. But I want it to twist midway. I am trying  to rotate it's segment on Y axis as in the image but it is not working.



Here on the left is what I want to achieve and right is what I have. I tried rotating the segment/vertex on Y axis but its not working.
You're looking for the Tilt (Ctrl+T) function.