Chris Boyd admits Lyon will be 'licking their lips' in anticipation of facing Saints after seeing them lose at Bath last Saturday.
But Saints boss Boyd can't wait for the challenge of taking on France's current top team, who have won eight of their nine league matches so far this season.
Lyon's only loss came at Clermont Auvergne on October 20 but they have since bounced back and they thrashed La Rochelle 45-17 last Sunday.
Saints, who will also face Leinster and Benetton in Champions Cup Pool 1, were beaten 22-13 at Bath last Saturday.
But all attentions now turn to this Sunday's European curtain raiser at Franklin's Gardens.
And Boyd said: "We're looking forward to it.
"They're all tough games and they're all tough pools.
"We went down to the launch last week and we saw how tough the pools are.
"All of the pools are demanding and ours is no different.
"Lyon were second or third in their log last year and they're top this year with eight wins and only one loss.
"They've got some really good players in there and they will get hold of our video from last Saturday and be licking their lips because they will think there will be a chance for them, which there will be.
"The big issue for us is that there are a number of players who will become available for us and we've got to carefully consider who we bring straight in, who we put on the bench and who we don't bring in at all.
"It's quite a big challenge and the Lyon game - while all games are important - has particular importance for us."
Despite last weekend's defeat at Bath, Saints are still in a healthy position in the Premiership table, sitting second, level on points with leaders Bristol.
And Boyd said: "We were always hoping to get three wins out of our first four games but the victory at Saracens in round one meant there was a possiblity we could get four out of four and we're disappointed not to have done that.
"But at the end of the day, it's only round four.
"We played Sale and Newcastle last year when they were both bottom and we've played Bath this time when they're bottom and lost again.
"At the end of the day, we were just a bit sloppy and inconsistent and there were things we didn't deal with."