And Richards also knew he had one task in particular - running.
"I knew that I'd be playing on him and you can do as much homework as you want, but basically you just write down, 'I have to run'," Richards said after the Swans' 15-point victory.
"That's his big strength and he does these long 100m leads side to side. I'll probably sleep pretty well tonight.
"Not many guys six-foot-six can charge around like that for four quarters and have speed as well."
Richards ran and ran well, getting the better of Riewoldt and playing a big part in the Swans' win.
Riewoldt was dangerous early, kicking his first goal from a free kick against Richards in the opening term and his second after out-marking the Swan in the second quarter as the Saints led by 10 points at half-time.
But Richards never stopped trying and regularly spoiled Riewoldt's marking attempts to limit the St Kilda captain to 15 disposals and 2.1, keeping him goalless after the main break.
"I thought he was really good 'Teddy'," Swans coach John Longmire said.
"He's done some great jobs for us this year.
"I thought he was outstanding and his ability in the one-on-ones was pretty good.
"He's played on some of the best key forwards going around for us and done a good job."
Richards produced one of the key moments in the game late in the second quarter when he thwarted what seemed a certain St Kilda goal.
With the Saints leading by 16 points in a tight contest, Adam Schneider found acres of space and bounded towards goal with Riewoldt in support.
Richards admits he was in two minds, but decided to pressure Schneider and managed to smother his shot on goal and help clear the ball out of the Swans' defensive 50m.
"Everything was going through my head," Richards said.
"I guess I was just trying to put some doubt in Schneider's mind.
"I thought if I push forward he'll handball over the top, if I stay back he can just run in, so I just tried to put some indecision in his mind and I think it might have worked.
"I'll claim it."
It doesn't get any easier for Richards next week, when he will again play a key defensive role at Skilled Stadium against Geelong's potent forward line.
