Having both qualified for the round of 16 by winning two of their three fixtures in Pool 2, both the Ospreys lying in third position and Pau, currently second on points difference, face off this weekend.
The winner of the clash will be rewarded will be a home tie in the knockout phase, something which Kelly says could provide a huge opportunity for the Ospreys to move forward with in the third block of the season.
How the knockout phase works
The four highest-ranked clubs in each of the three Challenge Cup groups will progress alongside the fifth-ranked clubs from the four Champions Cup sections.
In terms of knockout stages rankings, the clubs will be put in descending order based on their placings in their pool and then on the number of match points they have accumulated to create an overall list from 1 to 16.
The Challenge Cup pool winners will be ranked one to three with the top two teams having potential home advantage until the final.
The second-placed sides will be between four to six and the two highest-ranked third-placed clubs will be placed at seven and eight. Those eight sides will have home advantage.
The four teams that drop down from the Champions Cup will be ranked nine to 12 and the remaining quartet of Challenge Cup sides who have qualified will make up the final four spots from 13 to 16.

“We are very aware of the history in the European Cup and in any competition getting home advantage is huge,” said Kelly in his post-match press conference.
“It is one game at a time in terms of what we look forward to. Europe is special and is something we want to be successful in.
“It is all about opportunity, we have two wins in the bag, and we are going out there to make sure we can maximise it by creating the best chance of progress in the next block and knockout stages.
“We have qualified for the last four games even if you have home advantage, it doesn’t mean that you can’t be successful and get through.
“You would though be naive to think that having home draws all the way through doesn’t make a difference because it will and that is something we will be aware of.
“We want to be the best Welsh region and challenge for the play-offs and knockout rounds. It’s a huge opportunity as is really important for us and our season.”
The Ospreys show ten changes to the side that picked up a bonus point win against Newcastle last weekend with wing Ryan Conbeer returning from injury for his first appearance since October alongside an all-fresh centre pairing of Evardi Boshoff and Owen Williams.
Dan Edwards who was named in Wales’ Six Nations squad this week keeps his place at outside-half, partnering Kieran Hardy who is promoted to the nine jersey after scoring as a replacement last week.
Jack Walsh who scored two tries in the victory against Newcastle drops to the bench, replaced at full-back by Iestyn Hopkins.
The Ospreys pack sees the return of loose-head prop Steffan Thomas, hooker Lewis Lloyd and lock James Fender.
James Ratti and Morgan Morse come into the back row where captain Jac Morgan switches to open-side flanker with Justin Tipuric dropping out of the 23.
Rhys Davies, however, will miss out with the region awaiting an update after the lock suffered a reaction to a long-term knee problem on his comeback match against Cardiff in the URC on New Years Day.
“Rhys is not fit,” explained Kelly. “We are still waiting to hear from the physio to say exactly how long he will be out for and the details. He won’t be available for this weekend.
“It is never easy going to France especially when they are at home. If you look at Pau they have had some great results.
“We know it is going to be a tough test but also what everyone does it for, to get those opportunities to play in those games.
“It is exciting, and we are looking forward to the challenge ahead of us.”

Ospreys XV to face Section Paloise:
Iestyn Hopkins, Dan Kasende, Evardi Boshoff, Owen Williams, Ryan Conbeer, Dan Edwards, Kieran Hardy
Steffan Thomas, Lewis Lloyd, Tom Botha, Will Spencer, James Fender, James Ratti, Jac Morgan (captain), Morgan Morse.
Replacements:
Ethan Lewis, Garyn Phillips, Ben Warren, Lewis Jones, Tristan Davies, Luke Davies, Tom Florence, Jack Walsh.
[Lead image: Ospreys Rugby]
