Knights ended their seven-match losing streak, which began in their second fixture of the season, by beating Lions by three runs (D/L method) in a rain-hit contest in Potchefstroom.
While the Knights are out of contention of making the last four, Lions will face Cobras on Sunday in what is effectively a quarter-final clash at Paarl.
After limiting Lions to 125 for 8 in 20 overs, thanks to a collective bowling performance, Knights chased down the revised target of 110 off the last ball of their innings.
Fast bowler Hardus Viljoen, who had signed a Kolpak deal with Derbyshire this week, struck early in the chase when he had opener Patrick Kruger bowled for a four-ball duck. Rudi Second - the other opener - however, struck his third T20 half-century to drive the chase. He found able assistance from Leus du Plooy, who contributed 39 in an 81-run partnership for the second wicket. Dwaine Pretorius broke the stand in the 17th over, but Second stayed unbeaten with his captain Pite van Biljon to guide Knights home.
Earlier, having been sent in, Lions were reduced to 57 for 5 within 11 overs. Willem Mulder and Pretorius put on 41 for the sixth wicket to hint at a recovery, but Lions lost their last three wickets for 26 and eventually stumbled to the fifth defeat.
Intermittent rain meant that the clash between Warriors and Cape Cobras was abandoned without a ball being bowled in Port Elizabeth. The match officials ultimately called off the match at 8.06pm. The teams shared two points each, which meant Warriors drew level with Titans at the top with 29 points.