Sir Alex Ferguson felt his Manchester United side were worthy winners, but his Manchester City counterpart Roberto Mancini could not disagree more.
Robin Van Persie struck the winner off a wicked freekick in stoppage time, after Manchester City had come from behind to make it 2-2. Wayne Rooney scored his 149th and 150th Premier League goals of his career to put United 2-0 ahead, before Yaya Toure and Pablo Zabaleta made it 2-2.
Van Persie, a forward who City also coveted in the summer, however had the last word, whipping in a left-footed freekick to ensure all three points for his side and extend United's lead at the top of the Premier League table to six.
Ferguson said the victory tasted sweeter as United broke City's 37-game unbeaten record at home. The defending champions last lost at the Etihad Stadium on Dec. 20, 2010.
"We've done it to City in the past of course but this was special simply because they hadn't lost at home for two years," Ferguson said. "Both of us are contenders at the top of the league and it was an incredible game, you couldn't take your eyes off it.
"The intensity, passion, competitiveness... everything was there. And you've got to give credit to City for the way they keep going and for scoring late goals. They've done it again today (Sunday) against us. Fortunately we got the last one that counted.
"You know Robin's capable of that. It took a little deflection but it was a wicked hit and I'm really delighted it's flown in."
City had a lot of the possession, but failed to create too many chances, with United looking more potent going forward, and Ferguson felt the victory was thoroughly deserved.
"I think we played very well," Ferguson added. "I thought we were really fantastic today with some of our football and the game should have been out of sight in the second half with the number of chances we had.
"It's a funny game, football -- it would have been 3-0 with a goal (by Ashley Young) that was perfectly onside. Instead they go up the park and score (to make it 2-1) within minutes. That's the kind of game football is, it can kick you in the teeth that way.
"I also thought we should have had a penalty kick because I thought Patrice Evra was brought down.
"But there'll always be controversial decisions in a match like that because there are so many things happening."
City manager Mancini felt his side were unfortunate to leave without a single point, in a game which he though his side dominated. "It's very hard to lose a derby, but even more so in the last minute so I'm very disappointed," he said. "We dominated the second half and for this reason, I am really disappointed.
"They scored from their first two goalscoring opportunities but after that, we dominated the game and fought back really well, but we can't then give a goal away after working so hard.
"I think we made a mistake for the Van Persie freekick at the end by only putting three men in the wall. I wanted four but I couldn't get the instruction over and I think that cost us the goal.
"We should have defended this freekick better and we had chances to win this game, but there is nothing we can do about it now."