Waitaki retained the Leo O’Malley Memorial Trophy, affectionately known as the "peanut", in the 29-0, four tries-to-none win.
St Kevin’s last failed to score a point in the interschool match in 1995, when it went down 3-0.
Waitaki almost opened the scoring within the first five minutes after a penalty attempt by second-five Mason Kinzett hit the right-hand upright, before dropping behind the try line.
A fortuitous bounce for St Kevin’s was the only thing that saved it from going behind early.
However, prop Tonga Malafu barrelled his way through the St Kevin’s defence a few minutes later and Kinzett slotted the conversion to put Waitaki Boys’ ahead 7-0.
Halfback Thomas Hutton, who had a strong game for Waitaki, added another try at the 15-minute mark following a solid scrum and Kinzett added the extras to take his side out to a 14-0 lead.
St Kevin’s was starved of ball for much of the first half and when it did have possession was unable to capitalise on limited chances.
It barely got out of its own 22 in the first 15 minutes and struggled to cross the halfway line at all in the first 35 minutes.
While St Kevin’s defended well in patches it was unable to stop hooker Siketi Tevao latching on to an errant pass on the stroke of halftime and sprinting away for a 60m intercept try.
Kinzett curled in the conver sion from close to the sideline to extend Waitaki’s lead to 21-0.
Playing with a helpful wind behind it in the second half, St Kevin’s improved on attack and pressured the Waitaki defence through enterprising play, but was let down by poor handling.
St Kevin’s put in a quality defensive effort in the second half and held Waitaki out for long periods until replacement player Zac Uerata scored in the left-hand corner with only a few minutes left on the clock.
Tevao, Hutton, Kinzett and first-five Jake Matthews were outstanding for Waitaki while Samuela Babiau and Ovini Saro were standouts for St Kevin’s.