Since then things haven't gone to plan for Williams and co with back-to-back defeats to Clermont all but ending their hopes of reaching the knock-out stages.
But Williams insists there is plenty to play for in Paris.
He said: "Racing are a big physical team and their line outs been going well for them. Our forwards have been working hard on that area this week - our set piece is going to be massive for us on the weekend in terms of winning ball.
"It was disappointing to come away with a draw against them at home. If someone had said at the start of the season that we'd have won and drawn the first two games in the Heineken Cup we would have taken that but afterwards we felt we should have been at the top of the table after the first two rounds and won both.
"It'll be a different challenge going out to Paris on Friday but it's one we're looking forward to. There are a few new boys in the backline and getting game time together will make us bond a bit more and read each other better."
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