Northampton (8) 19 Tries: Ashton, Reihana Pens: Myler 3 Saracens (3) 3 Pens: Goode
Full-back Foden was voted man of the match for Saints
Tries from wingers Chris Ashton and Bruce Reihana and three penalties from Stephen Myler secured victory for Northampton in the LV= Cup.
Saracens took an early lead after Alex Goode sent over a penalty.
But the hosts were in front at the break thanks to Ashton's try and a penalty from Myler.
And in an uneventful second period, a try from New Zealander Reihana and a further two penalties from Myler ended Sarries' hopes of a comeback.
Northampton coach Jim Mallinder:
"This game is all about winning and gaining momentum.
"What we didn't want to do was lose two games in the middle of the season.
"We were really pleased because we managed to rest a few players last weekend and still sneak a win against the Ospreys and then come here and back that up with a second win."
Saracens director of rugby Brendan Venter: "Northampton bring the full metal jacket but there were a couple of vital decisions going against us.
"The sin-binning decision before half-time was unbelievably harsh and there were a couple of decisions in the second half where the referee saw things very differently to what we did.
"I thought the crowd and their scrum-half got to the referee and his touch judges. That's a dilemma."
Northampton: Foden, Ashton, Clarke, Downey, Reihana, Myler, Dickson, Tonga'uiha, Sharman, Gonzalez Bonorino, Day, Kruger, Dowson, S. Gray, Wilson. Replacements: Ansbro for Clarke (75), Dickens for Dickson (75), J. Gray for Sharman (74), Vickers for Gonzalez Bonorino (70), Hopley for Wilson (74). Not Used: Waller, Cannon, Everitt. Saracens: Haughton, Cato, Penney, Sorrell, Short, Goode, Barrett, Lealamanua, Reynecke, Nieto, Kruis, Botha, Barrell, Saull, Wray. Replacements: Gill for Lealamanua (51), George for Reynecke (67), Mercey for Nieto (35). Not Used: Vyvyan, Melck, de Kock, Farrell, Ratuvou. Sin Bin: Mercey (40). Att: 12,037
Ref: Gwyn Morris (Cardiff).