However, a surprise 14-9 defeat at Rugby Parma has left Bourgoin - tournament finalists last May when they were beaten 15-3 by Northampton Saints - needing to win on the road and qualifying for the knock-out stages of a tournament they won13 years ago.
"We have to win against Leeds, there is no other option," said international prop Olivier Milloud. "We know it will be a tough encounter, especially as we are playing away, but let's hope that we will take the positive from our results against them in Round 1 into the second leg.
"And we've shown we can get wins on the road so we will not dwell on that aspect. I have never played against Leeds but the main aims will be to earn a large territorial advantage and be strong in defence.
"We have managed to rotate our squad so we are relatively fresh and thankfully we do not have many injuries so we should be in a position to pick a good squad.
"I've been enjoying being back on the field after my injury and I'm still working to get back to my best level and my fitness is progressing slowly but surely.
"Our improved situation means we can stay on the right track and capitalise on our recent performances, though we must take care not to become slack and waste all those efforts."
"We got a try bonus point win over Bucuresti Oaks at the weekend so we achieved what was necessary, and, despite a somewhat questionable performance in the second half in which we probably loosened our efforts, we did the job.
"Now we will have to come up with an improved game and performance on Sunday otherwise it will be a real struggle - we will have to produce a full 80-minute game.
"We have got a lot of work to do this week to get things right. The weather conditions may have caused some disruptions in our training schedule and organisation but it is the same for a lot of other clubs and at Bourgoin we have known each other and trained with each other for a long time so we know what we've got to do to prepare as best as we can.
"And overall we are happy with the results we've had so far - with the exception of our faux-pas at Rugby Parma in Round 3 - and the ambition still remains to go all the way. What we want is to repeat the performance from last season and end up in the final."
And head coach Éric Catinot added: "Quarter-final qualification is in the balance at Leeds.
"It is obvious that we will have to improve our game compared to last Thursday night but having said that I don't think we will show the same profile on Sunday.
"What we want is a win at Leeds - that would be the best scenario possible as we hope to return to another Challenge Cup final. That is one of our objectives."