Forcing an enemy out of a fight for a "1v1" will make Mord pick or ban in pro play.
You need only a way for him to get in rage for it...

and he will be able to remove a high value enemy from a team fight.
Don't act like this won't happen. Intended or not it is going to be used for this reason. Enemy Kog is in a protect the Kog team comp? Mord jsut removed kog and the Lulu, Janna and Karma are now left with no high value target to defend.
Enemy Yasuo finally came online and is winning team fights? What team?
They did not give Fiora this kind of ult for this exact reason.
And this 1v1 can last up to 7 seconds.
, guess what Mord is going to do? He's going to ult the only champ that can actually create an infavorable situation for the Aatrox. For example,
's E is probably the strongest counter to Aatrox in the game. Morde Ults Morgana, and Aatrox kills the other 4 after landing a team infernal chains..... and the team fight is instantly won.