The Millers stretched their unbeaten run to eight games with a scintillating performance against one of their promotion rivals.
Goals from Michael Ihiekwe, Dan Barlaser and Freddie Ladapo put the Dons to the sword as Warne's side delivered another statement of intent.
Their promotion credentials were going to be put to the test in a three-game week and seven points from games against Portsmouth, Wycombe and Dons showed they are the real deal.
Ihiekwe put the Millers in front at Stadium MK when he headed home Barlaser's free-kick and the midfielder doubled his side's lead after the break when a corner missed everyone and went in.
Striker Michael Smith is trying to claim he got a touch, but Opta – the official data providers – awarded the goal to Barlaser.Substitute Freddie Ladapo then made it a rout with a cool finish as the Millers stayed in fifth, just three points off top spot.
Warne said: “I’m really pleased that was a good away performance against a really good team.
“I thought we had flashes of absolute excellence but it was all down to the lads' dedication and our out of possession stuff was absolutely frightening.
“They are really well coached by Rich (Barker) and Hammy (Matt Hamshaw) and the last meeting before we came we showed the lads the clips and asked them what they were going to do and we just know they are really good to coach.
“They had the gameplan on lockdown, it is one thing saying it in the classroom and another doing it on the pitch.
“I'm not saying we were faultless and there are still things that we need to improve on, but that was pretty damn close to a faultless display.”
The only thing that soured the afternoon was Warne picking up a yellow card after disagreeing with a decision erratic referee Christopher Sarginson made.
The fine is £10, purely for administration purposes, and Warne says he will have some making up to do.
“It was my first yellow card, I found it very frustrating in the first half and obviously I lost all control because I threw a bottle down, not near the fans, near my own feet,” Warne said.
“I am disappointed I got booked, my mum will definitely text me her disappointment face so I will have to build bridges with my family for the rest of the week.”