I was playing on this map, ( im not really sure which map) and there was a corner and a ct in the corner and there was a ledge above him. So i took the opportunity and grabbed my knife jumped down, LANDED on his head and looked down and started to knife him. But the thing was that i couldn't knife him. As he kept crouched and was looking around was friend yelled out HEY UULUUBULUU CROUCH DOWN NOW. So I crouched down and knifed him and won the game (: .
&btw the session for when i was on his head TRYING to knife his was roughly a minute.