Any kind of CC. I personally tested templar spear, fear. and destro clench. you are able to constantly CC your enemy within a duel.
THE CAVELRY HAS ARRIVED! Cav is a professional magblade, (in his not so professional opinion). He is immortal and is fighting for the Pact since 2E 572, amidst the turmoil of the Second Akaviri Invasion. He protects the provinces of Skyrim, Morrowind and Black Marsh.
Check out his PVP YouTube channel !
https://youtube.com/TheCavalryPK