Gaining revenge for a 41-13 loss at Ellis Park at the start of the campaign, Bulls saw off a late rally from their third-placed opponents to move up to sixth.
An error-strewn opening with penalties for both sides saw the Bulls lead 9-6 thanks to a trio of kicks from Jacques-Louis Potgieter and they scored the game's opening try when Ulrich Beyers burrowed over following a storming 50-yard run from the impressive Grant Hattingh.
Potgieter nailed the first of three conversions and further penalties meant a 19-12 scoreline at the interval before Burger Odendaal ran on to a deflected 50th-minute grubber to give the Bulls breathing space.
A 29-12 lead became 29-26 as substitutes Kwagga Smith and Martin Muller went over for Lions - both tries having extras added by Ruan Combrinck - but second row Hattingh secured the try his display deserved to deny the visitors a bonus point.
Fly-half Francois Brummer slotted a late drop goal to give Griquas a 21-18 win over defending champions Sharks at Kings Park.
A try from prop Thomas du Toit looked to have salvaged a draw for Sharks but visiting captain Brummer held his nerve after the final hooter sounded.
Griquas held a 15-8 half-time lead as full-back Gouws Prinsloo landed five of his six successful penalties during the opening 40 minutes, with Du Toit's front-row colleague Lourens Adriaanse scoring the game"s first try against his former club after 24 minutes.
In the day's earliest kick-off, Pumas secured a first away win of the campaign with a dominant 31-17 triumph at Free State Cheetahs.
Hennie Skorbinski, Rosco Speckman and Marius Coetzer all went over for Pumas and Cheetahs were made to pay for a ragged display.
JP du Plessis and Sarel Pretorius scored the home team's tries but they will reflect on wasted opportunities in the opening half and a slack approach to getting numbers to the breakdown, as they turned over regularly.
On Friday, Western Province made it five wins from five with a comprehensive 49-14 trouncing of rock-bottom Eastern Province Kings.
Juan de Jongh and Siya Kolisi each crossed twice in a dominant display from the leaders.