Wasps, who finished seventh in the Aviva Premiership table, recovered from shipping a season high 74 points in defeat to Northampton last weekend to beat their visitors from Paris 30-29, though needed an 80th-minute penalty from former England fly-half Andy Goode to do so.
But with such a slender advantage going into next Saturday’s second leg across the channel, Young admitted to having mixed emotions.
“We’re a little bit frustrated because we gave them some easy points, but loads of positives as well,” said the 46-year-old.
“Now we need to go up there and win. We’ll go up there full of confidence.”
With a place in next season’s premier European competition at stake, Wasps led 13-12 at half-time with Tom Varndell touching down.
Ashley Johnson and Joe Simpson added further scores in the second half to delight the Adams Park crowd, but Wasps required a last-gasp penalty from Goode to nab the win after conceding 12 points in a calamitous 60 second-spell.