Despite lasting only 30 minutes he was substituted at half time the Limerick U-21 star did enough damage in that opening moiety to ensure the defending champions remain firmly on course for their third Harty title in a row.
Originally fixed for the Mon field, the game had to be switched due to fog but it made no difference as O'Shaughnessy and his colleagues went on a scoring spree.
O'Shaughnessy bagged a hat-trick of goals in the opening 15 minutes which effectively ended this game as a contest and he added a fourth eight minutes later which helped his side to an interval lead of 5-8 to 0-4.
Despite the fact that O'Shaughnessy didn't appear for the second half, the Fermoy college continued to dictate matters in every sector, with Brian Lane, James Dorgan and Conor Griffin unbeatable in defence and Mark Cleary, Paul Kearney, Michael Allen and Fergus Browne scoring freely in attack.
The excellent free-taking of Colin Fogarty and Brendan Barry helped Youghal to double their first half tally but scoring only two points from play, in comparison to Colman's 8-12, is a clear indication of the enormous gap there was between the sides.
Further goals by Mark Cleary, Padraig Cotter and a superb effort by Fergus Browne completed the Colman's scores and it would be a brave man who would bet against him winning the Harty title for the third year in a row when the competition resumes after Christmas.
Youghal battled bravely and showed some nice touches but the odds were overwhelming. Only Colin Fogarty at centre back, with three excellent points, and their two Cork minors, Brendan Barry and Brendan Ring threatened up front against a Colmans' defence that never put a foot wrong.
Scorers: St. Colmans; A. O'Shaughnessy 4-3 (0-1f), F. Browne 2-1, M. Cleary 1-1, M. Allen 0-4, P. Cotter 1-0, P. Kearney 0-2, C. Coakley, P. Hyland, E. Condon 0-1 each.
Youghal CBS; B. Barry 0-4 (0-3f), C. Fogarty 0-3 (frees), B. Ring 0-1.
ST. COLMANS: D. Fitzgerald, J. Dorgan, B. Lane, C. Griffin, S. Barrett, K. O'Mahoney, J. O'Donnell, S. Stack, E. Condon, P. Kearney, M. Cleary, C. Coakley, A. O'Shaughnessy, F. Browne, M. Allen, subs. b. Horgan for O'Shaughnessy, P. Cotter for Stack, P. Hyalnd for Kearney, J. Herlihy for Coakley, S. Russell for Dorgan.
YOUGHAL: E. O'Donovan, E. Kelly, K. Dunne, D. Coyne, J. Collins, C. Fogarty, N. Beresford, B. McCarthy, B. Harnedy, E. O'Loughlin, B. Ring, C. O'Keeffe, N. Roche, B. Barry, E. Ahern, subs. E. Colman for Coyne, M. O'Neill for Kelly, L. Desmond for Ahern, M. O'Brien For Roche.
Referee W. Horgan (Brian Dillons).