A brace of first-half tries from left-wing Roddy Fitzpatrick were of immense importance at Balbriggan RFC as Gonzaga College held off a late surge from King's Hospital to book their place in the quarter-final.
The Ranelagh school had opened the scoring with nine minutes gone as a sharp pass from a scrum by Nick Peters provided the platform for his half-back partner Ross McKeever to secure a seven-point salvo, and the No 10 also supplied the bonuses to the pacey Fitzpatrick's magnificent try just four minutes later.
King's Hospital were struggling to maintain a rampant Gonzaga and, although they forced their way back into the reckoning courtesy of an unconverted five-pointer by flanker Connor Spillane, a terrific stoppage-time score from outstanding winger Fitzpatrick ensured that Gonzaga brought a commanding 19-5 lead into the second period.
Any chance that the Palmerstown side had of swinging the pendulum in their direction seemed to disappear nine minutes after the restart when a neat off-load by influential skipper Andy Marks set-up a try for his midfield partner Oscar O'Clerigh.
But bustling No 8 Matthew Bursey breathed fresh life into King's Hospital's challenge by touching down on the right-hand side with 15 minutes remaining.
Gonzaga's line was subsequently breached for a third time at the very end of normal time but, though fly-half Daniel Courtney also kicked two measured conversions, it proved to be a case of too little, too late, as Gonzaga now focus their minds on a last-eight showdown with St Andrew's College.
GONZAGA COLLEGE – B Goulding (D Meenan 65); K O'Connor, O O'Clerigh, A Marks, R Fitzpatrick; R McKeever, N Peters; E Byrne, G Rumley (S Holly 67), R Barry; C Horan, T Mays; P Ryan (F Keane 39), F Ryan, M McVey.
KING'S HOSPITAL – R Lawless; L Morgan, R Olusa, W Potterton, D Byrne (M Brennan 65); D Courtney, R Sharkey; D Ables (C Petit 36-65), R Charman (C Murphy 55), N Mipko; F Shilling, C Kerr; J Hogan, C Spillane, M Bursey.
REF – C Dawson (Leinster Rugby).