After the match, as people discussed the crazy game, I heard Manchester City had lost to Sunderland, with the former City player Adam Johnson scoring the game's only goal.
I drove home, looking forward to seeing Johnson's reaction to his goal.
It was seldom the case when I played, but there is a trend for players not to celebrate scoring against their former clubs.
They probably feel they do not want to make enemies at a club they had enjoyed playing at.
Cristiano Ronaldo even announced last week that he will not celebrate if he scores against Manchester United - the club where he spent six goal-and-trophy-laden years - for Real Madrid at Old Trafford on March 5 in their Uefa Champions League match.
I can understand the sentiment, but how does he know how he is going to feel if he scores a last-minute winner?
I thought Johnson would be different, that he would go crazy. He did not leave City on the best terms, having publicly criticised his manager, Roberto Mancini.
Johnson, a decent winger with a lovely left foot which delivers a great cross, did well in Manchester and felt he deserved more first-team opportunities. He did not hide that opinion, while City felt he lacked the discipline and professionalism to play at the highest level.
There are two sides to every story, but Sunderland liked Johnson enough to spend £10 million (Dh48.4m) in August for a player born locally. Johnson's got time to justify that fee.
While he was outspoken at City, he played down his goal celebration against them on Boxing Day, when his 25-yard shot squirmed past his former teammate Joe Hart. He initially looked surprised that his shot had gone in, but then he shrugged his shoulders as if to say "if only".
Maybe it was out of respect for City fans, because he would have been absolutely buzzing. He will have been as happy as Mancini felt angry and cursed.
I know how it feels to score against your former club; I have been there and it is one of the best feelings in football. Ignore anyone who tells you differently.
Much can depend on how you departed from the club, of course.
Johnson will have felt rejected and had a chance to prove to his former employers it was a mistake to sell him. But even when you choose to leave a club, your departure is seldom amicable - though you might say different in public.
Returning players may say that they hope their former team does well, but they want nothing more than to prove a point. It might be to a manager, a chairman, former teammates or fans.
I was slaughtered by Newcastle supporters when I left for Manchester United. They accused me of being a waste of money, of engineering a move and called me a reject. That's right, they called their top scorer a reject.
Not all of them, but enough to be heard. I was not allowed to give my version of events because I was soon at another club where I was encouraged to look forward, not back.
What could I have said, anyway? The best way a footballer can answer his critics is with his feet.
I returned to Newcastle with bitter-sweet feelings. I was glad to see the kit man, the merchandise girls and the tea lady, people who had helped me in my time there.
I was glad to see the fans who did not get on my back, too, though it is hard to differentiate when you leave a team bus and see hundreds of people shouting at you. But I was so focused to ram their criticisms up their noses. And I did, too.
They were chanting that I was a waste of money - my sale made over £5m profit for Newcastle, by the way - when I scored a goal.
Did I play down the celebration? Not a chance. I celebrated as usual, with my teammates and in front of our own fans. I didn't rub it in to the Newcastle supporters; scoring made my point. I felt like I was telling my critics: "I'm not a bad player for a reject, am I?"
And that defiant attitude never left me whenever I played against Newcastle.
I would never have taken my family to a game there because someone would have been on hand to dish out abuse I did not want them to hear, but I did take my scoring boots.
I scored more goals against Newcastle than any other club in the English top flight - nine in 11 league games for Manchester United alone.
I scored home and away against them because I wanted to prove over and over again that they were wrong to doubt me, and that the criticisms were unjust.
Johnson must have had similar feelings, although he did not show it during the game. But I'm sure he raised more than a wry smile in the dressing room after the match.
Andrew Cole's column is written with the assistance of European football correspondent Andy Mitten.