This player seems to know every movement of his enemies. I spectated him for a while and saw the following:
the interrval between 00:00 and 00:35
There was no enemy on the minimap but somehow he knew exactly where his opponent hid.
He is aiming from B to C and in the given interval he follows the enemy movement with his crosshair, while there is no enemy to see or is hidden by the wall in C.