The Griquas surged to a 41-31 win over the Lions on Wednesday in a match that ended with the hosts playing with just 13 men at Ellis Park.
There was very little that separated the sides at the start of the second half, but a red card to Lions fullback EW Viljoen for a dangerous tackle swung the momentum of the match.
From there, Griquas seized control, while there was never going to be any hope of a Lions comeback after replacement Duncan Matthews was yellow-carded for a reckless cleanout at a ruck.
It was a result which moves Griquas – possibly temporarily – to the top of the Currie Cup log.
Western Province are set to face the Cheetahs in the second game on Wednesday evening.