The top four teams in the tightly contested group are separated by just a single point: Doncaster Knights and Rotherham Titans top the table with 10 points (Doncaster with a game in hand) while Ayr and Cardiff are on nine. Pontypridd are in fifth place.
With the pool so close, and Rotherham and Cardiff going head-to-head this weekend, the match which is expected to see around 400 traveling Ponty fans descend upon Millbrae, is crucial to the Ayrshire clubs chances of qualification.
Scrum-half AJ Macfarlane will start the match with Jamie Hunter coming in at stand-off.
Hunter’s arrival sees the competition’s top point scorer, Frazier Climo, move out on place to inside-centre.
Ayr coach Kenny Murray said: “Our last outing in this competition was against Birmingham and Solihull, at home, where we enjoyed an excellent 49-17 victory.
“Saturday’s opponents, Pontypridd, will provide a stern test as they are a strong, aggressive team and are lying third in the Principality Premiership behind Neath and Swansea.”
Looking ahead to the fixture he added: “We have really enjoyed this tournament. The players, coaches and club officials are keen to maintain a good home record not just for Ayr but Scottish Rugby too.”
Crucial to the permutations of qualification is that, while Doncaster and Ayr face the lowest and second-lowest teams in the group (both of whom are yet to register a win), Rotherham travel for a crucial clash against Cardiff.
15 Dougie Steele
14 Johnny McClung
13 Ross Curle
12 Frazier Climo
11 Cammy Taylor
10 Jamie Hunter
9 AJ MacFarlane