The Lions beat the Kings 41-31 in front of 18 000 fans at Ellis Park.
With the Kings having replaced the Lions in Super Rugby, this was always going to be more than just another pre-season hitout.
The Lions played like they had a point to prove and led 22-7 at the break thanks to tries from lock Hendrik Roodt, flanker JJ Breet and tighthead prop Ruan Dreyer, while lock Rynier Bernado went over for the Kings.
Roodt grabbed his second five minutes after the break, before the Kings responded through scrumhalf Johan Herbst.
Replacement flank Warwick Tecklenburg’s try made it 34-14 with 20 minutes to go, but Herbst and former Blues centre Hadleigh Parkes hit back for the visitors.
George Whitehead then slotted a penalty with six minutes to go to reduce the deficit to three, but the Lions put the result beyond doubt when they won a 5m lineout and Tecklenburg went over from a maul that the Kings chose not to contest.