First Division log-leaders Boland were shocked 37-27 by the bottom-of-the-log Griffons on Friday night.
The defeat was the Cavaliers second of the season, and will give them plenty to think about before their semi-final against Eastern Province in Wellington next weekend.
Boland outscored the hosts by five tries to four, but Justin Peach had a nightmare with the boot, succeeding with just one kick at goal.
The Griffons led 24-15 at half-time.
Griffons - Tries: Cecil Afrika, Clinton Prinsloo, Gabriel Kennard, Sandile India. Conversions: Prinsloo (3). Penalties: Prinsloo (3).
Cavaliers - Tries: Angelo Brinkhuys, Carl Wannenburg, Claude Arendse, Jongi Nokwe, Rayno Benjamin. Conversion: Justin Peach.