The former Glanmire star, who will play professionally in Spain next season with Arxil Pontvedra, was simply awesome as she almost single-handedly defeated the touring American college side.
The class of O’Reilly helped the home side into a 7-0 lead in the second minute.
Yale slowly got to grips with the Cork side but, with Grainne Dwyer also showing deft skills, Montenotte deservedly led 20-16 entering the second quarter.
On the resumption it was evident that Montenotte were struggling to cope with their opponents on the boards as the Americans picked up a lot of easy baskets ten feet from the hoop.
But the home side, following the introduction of Stephanie O’Sullivan, tightened their defence and, with O’Reilly a constant threat, Montenotte led 29-25 at the break.
There was little to choose between the teams in the third quarter as they traded baskets for long periods, with the teams tied at 40 points apiece entering the crucial period.
Coming down the stretch Yale, thanks to the outside shooting of Janna Graf and Sarah Halejan, went ahead and held out for a hard-fought three point win.
Top scorers for Team Montenotte: O O’Reilly 28, G Dwyer 12, K Bland 4.
Yale University scorers: S Halejan 19, J Graf 16 H Latham 6.
TEAM MONTENOTTE: G Dwyer, H McCarthy, O’Reilly, C McCarthy, L Dennehy, V O’Driscoll, K Bland, L Falvey, S O’Sullivan, K Walsh, A Dunlea, C O’Brien.
YALE UNIVERSITY: E Allen, A Byant, M Boardman, Z Keita, S Halejan, W Wyoff, A Osborne-Jones, N Sarju, A Tyson, H Latham, L Thomer, J Benton, C Fitzpatrick, L Snecinski, J Graf.
Referees: S Gabor & J Houlihan (Cork).