D3 has a better recovery, can survive long vs ike due to weight, has attacks that are just as disjointed as ike's, and his throw and gimp game are miles above ike, which is what helps him win this match. His throw game allows him to easily get ike off the stage, and his disjoints and multijumps help keep him off.
Essentially, ike's weakneses is something that D3 is naturally great at exploiting (poor and/or linear recoveries.)
Edit: and let's not forget the projectiles with huge hitboxes, making sniping easy.