The game bore all the hallmarks of a relegation dogfight, with many errors, and not a little niggle at times.
Both Richard Parks and Scott Morgan can count themselves fortunate to have remained on the pitch after separate scraps at rucks and mauls. Steve Leyshon did well to control the game, but he had his work cut out.
Tim Stimpson had a game which he will be happy to banish from the memory, fumbling a number of passes and catches, and eventually leaving the pitch with an injury inflicted by Johnny Howard's scything tackle.
Leeds opened the scoring in the 12th minute, Gordon Ross landing a medium-range penalty
Andrew Blowers, back from a concussion-enforced three-week break scored the first try of the game after 19 minutes, but Ross replied with another penalty immediately after.
The Saints kept their forward momentum going though, and England winger Ben Cohen burst onto a pass from Shane Drahm after 25 minutes for the second Saints try, after Drahm's clever run had split the Tykes defence.
Drahm converted Cohen's try, rounding off the first-half scoring, and added a 63rd minute penalty to put the Saints 15-6 ahead.
Ross replied to keep Leeds within bonus point distance, and the Leeds pack were in clear ascendancy in the closing stages.
But with Drahm punishing Leeds with another long-range effort following a trademark Bruce Reihana counter-attack, Northampton again had room to breathe.
Matt Cardey was close for Leeds in the dying minutes, and the Tykes will be massively disappointed to come away from the game empty-handed, as their efforts deserved at least a bonus point.
For Northampton:Tries: Blowers, CohenCon: DrahmPens: Drahm 2
For Leeds:Pens: Ross 3