Owen Farrell slotted over three penalties and converted Alex Goode's try to help end Saints' perfect record, the hosts only responding with three points apiece from Stephen Myler and Ryan Lamb.
There was a worrying start for the Northampton front row as they lost their own scrum on their 22. But Dylan Hartley made up for it by getting over Brad Barritt to win a penalty on his try-line after opposite number Schalk Brits looked to have set up a try when he offloaded five metres out.
Nevertheless, with the help of a strong wind Farrell put Saracens 3-0 in front with a penalty from the halfway line after eight minutes.
Some good work on the right wing from the Pisi brothers got the home side into the Saracens 22 and a shot at the posts. George Pisi flicked a pass out of the back of his hand to brother Ken who nipped past a tackler before Saints won a penalty at a ruck, allowing Myler to make it 3-3.
When Ken Pisi gave the ball away Saracens counter-attacked to score the game's opening try after 26 minutes.
Brits nipped on the outside of Soane Tonga'uiha to send Joel Tomkins free on the right wing and his inside pass put Goode over. Farrell made no mistake with the conversion.
Saints came out for the second half without captain Hartley, but the pack still turned over a Saracens scrum and the resulting attack earned them a penalty for Lamb, now kicking in swirling rain, to trim the lead to 10-6.
Saracens were winning the important battle at the ruck, however, and their suffocating defence earned them further penalties for Farrell to make it 16-6. The positive result lifts them top of the table, two points clear of Saints.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.