The Blues have won only once at Old Trafford since 1974 - but Richards was part of that 2-1 triumph in February 2008.
When he looks down the team sheet from that day, it convinces him there is no reason why they cannot do the same again.
He said: "There's only me and Joe Hart left from that day. So many players have come and gone since then, I'm just happy to be still around it.
"We beat United then and we didn't have half as good a team as we've got now - so we have to go there with some confidence.
"I remember Darius Vassell got the first one and Benjani did his celebration. It was a great day for Man City and our fans back then.
"We were only around mid-table then so it was a massive achievement for us to win there."
So has he told his new team-mates what the secret is?
He said: "I wish I knew what it was, I've been on the losing side enough times since. I'm still trying to work it out.
"We know we are capable of giving them a really good game but at home they pose a really big threat, there's no doubt about that."