They say that the grey wolf is the closest living relative of the dire wolf. That’s not really true. Rather, the dire wolf is equally related to all extant members of the subtribe Canina. Canina includes jackals, African wild dogs, dholes, wolves (not including maned and Falkland Islands wolves), domestic dogs and coyotes.
I believe that it convergently evolved traits similar to the grey wolf. Or perhaps both the dire and grey wolves retained traits lost in other Canina, but I think it was mostly convergent evolution.