A dramatic injury time winner from Jon Otsemobor clinched victory for MK Dons as they knocked out AFC Wimbledon to book a place in the FA Cup third round.
The hotly anticipated match was the first time the two teams have met since the formation of AFC Wimbledon, created by Wimbledon FC in protest against the club’s proposed move to Milton Keynes.
Wimbledon FC went ahead with the move and were renamed MK Dons in 2004.
The atmosphere in the crowds was intense but stayed incident free, though AFC fans made their contempt for their rivals clear by chanting: "You know what you are, you franchise bastards", reported the Guardian.
The first 30 minutes failed to live up to the hype with neither keeper being called into action. The most notable event was a plane chartered by AFC fans that flew overhead tailing a banner reading: "We Are Wimbledon".
Stephen Gleeson opened the scoring for MK Dons with a stunning 25-yard strike that soared into the top right corner.
AFC couldn't find a reply until the 59th minute when Jack Midson headed a Toby Ajala cross into the net.
The emotion was too much for some fans who burst on to the pitch to join in the celebrations, reports the BBC.
A goal from Ryan Lowe for the Dons was disallowed for an offside flag against Zeli Ismail.
Then, in the dying seconds Ismail took advantage of a failed AFC clearance when a shot hit the ground only for Otsemobor to get a touch to hook the ball over Sullivan in goal.
MK Dons manager Karl Robinson told the BBC: "It's been a tough week. It's been enjoyable but it's also been difficult.
"I thought the game typified two sets of teams with great hunger and passion for the club they play for. Two teams can walk away from this stadium very proud of each other.
"I wanted this game to go smoothly, I wanted it to be conducted in a manner that was right for the English game and I thought we all did that.
"Maybe I got a bit excited with the goal at the end but I'm not going to apologise for that.
"I love this club and the players who wear our shirt. I'm sure you'd rather see me celebrating like a lunatic than just stood there with a stone-face smile."
AFC Wimbledon manager Neal Ardley said:"I've got mainly pride. Pride for the players. We worked hard on a game plan and we felt it was the best way we could cause an upset. Every single player to a man carried those instructions out.
"They got a great first goal and a bizarre second. But we were inches from going in front so we can't ask any more than that.
"My main fear was not doing the fans proud and I can sit here now, despite hurting from the defeat, and say we did that.
"We knew we would end up having very little possession. We knew we couldn't press them high up the pitch because they play between the lines very well.
"The game plan went to a tee but we were hoping for that stroke of luck and perhaps that wasn't with us."