This wasn't so much the clash of two teams but the clash of two cultures.
Hibs are buzzing these days. They're making chances and scoring goals, they're conceding little at the back and playing with verve and hunger all around the pitch.
United had the comfort of a win, at last, against Ross County at the weekend, but their recovery was halted emphatically in its tracks right from the get-go.
We wondered if Hibs could match the high-octane tempo they showed when beating Rangers on Sunday - and they did.
In the opening 15 minutes, they carved out three decent chances, their front three of Cummings, James Keatings and Dominique Malonga causing havoc.
United didn't know what to do with any of them. Behind the front three, John McGinn, tidy as you like, pulled the strings. All around the pitch, Hibs displayed a hunger for work and an accuracy in possession that Mixu Paatelainen's side couldn't get near.
Jason Cummings scored Hibs' second goal from the penalty spot in Edinburgh
The opening goal came on the back of more of that heavy pressure. Keatings had just forced a save from Michal Szromnik in the United goal, a prelude to Mark Durnan pulling off a goal-saving tackle on Cummings.
The United goal was being peppered so often that it was inevitable that the breakthrough would come.
It arrived courtesy of Gray, who rifled a shot past Szromnik in the midst of the onslaught.
The visitors had to content themselves with playing on the break - and it rarely worked.
McGinn almost made it 2-0 direct from a corner, Szromnik scrambling madly to keep it out. It was a frenetic scene in the United defence and a story of their night.
They were vulnerable so often. A sitting duck to a team that is bursting with ideas and goal-threat.
Paatelainen would have given his players a rocket at the break, but it did no good. Less than a minute into the new half, Keatings thumped a shot off Szromnik's post.
United had a moment, when Ryan McGowan flicked an effort on goal, but Stevenson dealt with it comfortably enough and away went Hibs again.
Chances came in a steady flow and soon the second goal arrived too. John Rankin was done for handball in the box and Cummings punished him.
There was scarcely a shred of doubt that he would put it away. The striker has now scored in his last six games. A precious goal machine.
Murray had that chance late on, but he fluffed it. Farid El Alagui came off the bench for Hibs and fluffed one of his own, the fluff to beat all fluffs. It didn't matter.
Stevenson might have been fortunate to see his shot at the end deflect past Szromnik, but the three-goal advantage was entirely just.
Four, five or six goals would have been just. The gulf in class was that wide.