Late tries from Luther Burrell and George North gave Jim Mallinder’s men hope as the clawed their way back to four points behind with four minutes to go.
But Saracens, who had been in control at 28-10, clung on to cement their place at the top of the table.
Tries from David Strettle, Kelly Brown and Marcelo Bosch looked to have left Saints with no way back heading into the final stages of the game.
But a Matt Stevens sin-binning eight minutes from time and the quick Burrell and North scores, allied with successful conversions from Stephen Myler pushed Saracens all the way.
Saints had been ahead during the first half as a penalty try and Myler’s boot gave them a 10-5 lead.
But Saracens went on to boss proceedings as they looked set to record a convincing win.
And although Saints had other ideas, Mark McCall’s side held out to record a victory that puts them 10 points clear at the summit.
For Saints there is still plenty of work to do to secure a top-two spot as they are now just three points clear of Leicester with three games to play.
They headed to Saracens hoping for a similarly slick start to the one they enjoyed on their last visit, when they raced into a 17-0 half-time lead in last May’s play-off semi-final.
But it was Saracens who were out of the blocks quickest on this occasion as Owen Farrell’s fine grubber kick teed up Strettle, who touched down in the corner.
Farrell missed the conversion and Saints quickly cut the gap to two points as Myler fired a penalty through the striking red uprights.
And Saints were soon in front as they steamrollered Saracens with a driving maul giving referee Matthew Carley no choice but to award a penalty try.
Myler made it 10-5 with the conversion, but the home side were soon back on the front foot, with Brown making the most of an advantage out wide to dance in for a score.
After a quick rendition of the Proclaimers greeted Scotland flanker Brown’s effort, Farrell kept his composure to give his team a two-point lead.
And Saracens continued to push on in search of a third, soaking up some huge Saints hits that drew groans from the supporters.
They had stopped the try, but the men in lime soon conceded another penalty, inviting Farrell to add to his team’s tally, but his kick went astray.
Another monster hit from Courtney Lawes demonstrated Saints’ desire for the occasion but Saracens were bossing territory and a whopping kick from Bosch extended their lead.
Bosch was at it again moments later as Jamie Elliott ran into trouble, giving Sarries a shot at goal, which their Argentine centre landed with aplomb.
Saints needed to stop the penalty drain and get some possession in the opposition half but they simply couldn’t get out.
Saracens were swarming forward at every opportunity and another penalty gave them a 21-10 half-time lead.
Injury forced Farrell off at the break, with Charlie Hodgson on in his place, and Saints knew they needed to put the new man under pressure at the start of the second half.
A typically rambunctious run from North refuelled Saints’ belief but they were being met by some stern Saracens resistance.
And the home side were still menacing in attack with a poor pass from Myler seeing George Pisi fumble and Saracens used the ball to great effect, with Bosch scoring.
Hodgson made it 28-10 with the successful conversion, leaving Saints with a mountain to climb.
But the away side were helped by Stevens’ sin-binning with eight minutes to go and they took advantage of it quickly as Burrell stretched out an arm to score.
Myler reduced the deficit to 11 points and Saints were pushing on as North barrelled his way over in the corner.
Myler brought his team back to within four points with four minutes to go and having looked so convincing throughout the game, Saracens were rocking.
But, despite some late pressure, the league leaders clung on to ensure Saints face a real fight to fend off Leicester in the battle for the top two.
Saracens: Wyles; Ashton, Bosch (Streather 72), Barritt, Strettle; Farrell (Hodgson 40), de Kock (Wigglesworth 50); M Vunipola, Brits (George 50), Johnston (Stevens 50); Borthwick (c), Botha; Wray (Burger 72), Brown, B Vunipola.
Replacements not used: Barrington, Sheriff.
Saints: Foden; Elliott, G Pisi (Wilson 70), Burrell, North; Myler, L Dickson (Fotuali’i 53); A Waller (E Waller 55), McMillan (Haywood 53), Ma’afu (Denman 55); Lawes, C Day (Dickinson 55); Clark, Wood (c), Manoa.
Replacements not used: Dowson, Hooley.
Referee: Matthew Carley