The Blues had not lost in the Barclays Premier League at the Etihad Stadium since 20 December 2010 when Everton won 2-1 there. Thirty-seven games later, their impressive sequence was shattered by Robin van Persie's last-gasp free-kick winner, after Yaya Toure and Pablo Zabaleta had cancelled out Wayne Rooney's first-half brace.
"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," said Sir Alex. "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 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."
When asked if he felt the Reds were worthy winners, the boss replied: "Absolutely. I think we played very well. 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.