City threw a two goal lead in August's Community shield to lose out to Sir Alex Ferguson's side in the sides' last meeting but the defender feels that the blue half of Manchester has caught up with the Old Trafford outfit.
Richards was speaking ahead of this weekend's Manchester derby and the defender is hoping for a feisty encounter at Old Trafford.
He told the Manchester Evening News: "United now know, much as they won't say it, that we are a genuine threat to them.
"We are not going out and saying we will win this game or that game, but they call us the noisy neighbours. I think they're a bit frightened."
"The last four derbies have not been that ferocious really, three or four years ago it was ridiculous, some of the tackling.
"I'd like to see that again, that ferocity, as it makes it more special. We all like to see nice football, but everyone loves a good tackle.
"It's harder these days, as if you tackle someone hard you get questioned. I preferred those ferocious derbies - if it's a foul obviously the referee has to pull it up, but with those 50-50 challenges he should just let the game flow."
The 23-year-old now considers the teams to be fairly even and is confident that Roberto Mancini's side are capable of picking up a result in their neighbour's back yard.
He continued: "It used to be the case that we went to United and got battered every time but in the last year or two we have gone to United and sometimes looked the better team, on their own patch, so it shows how far we have come in a short space of time.
"We have improved a lot and want the ball down to play - in those days it was about getting 11 men behind the ball and defending, and if we got a chance we had to take it. That's what we did.
"If you speak to Mancini he wants to go there and win. People talked about us last season being boring and negative, but if you watch us now we are completely the opposite."