Unknown to most, Kirk and Rawnsley were on the same split, which meant they were running the identical course and an impending head-to-head race.
With two controls to go they emerged, Kirk holding a 10m lead which dissipated to almost nothing at the last control before the 80m uphill finish.
Kirk dived for the finish control to limit his rival's options for a two-second win.
Twenty minutes later the finish for third was a replay.
Fraser Geddes, of NBHS, led into the last control after Mitch Keip (HNHS) hesitated but snapped out of it for a final sprint to clinch third place by a second.
Senior girls' honours went to Napier Girls' High School.
Carolyne Nel started the final leg with a lead fellow national team member Jenna Tidswell (HNHS) couldn't peg back. The three Bay schools will resume their fierce but good-natured rivalry at the nationals in Waikato during next month's holidays.