1999 final to win the treble is special, City winning the league like that was amazing but they have both been mentioned loads so I will go for a slightly older one in Arsenal vs Liverpool 1989 at Anfield. If Liverpool don't lose by 2 or more then they win the title on the last day of the season and in the 90th minute it is 1-0. That is arguably even better than the City one because it wasn't just a last minute goal to win the title, it was a last minute goal to steal the title from the team you are playing on that day at their ground.
Do you know what this thread is about? Of course they scored, it is called "most epic last minute winning goal EVER?" It would be a bit of a stupid post if they didn't score.