Northampton romped to a convincing 24-3 win over Aviva Premiership leaders Harlequins on Friday.
Northampton turned in a dominant display in front of another full-house at Franklin's Gardens to inflict Harlequins' second defeat of the English domestic season.
Saints were much smarter and more physical at the breakdown than the visitors, and all the eagerly-awaited England match-ups went their way in front of watching caretaker boss Stuart Lancaster.
Two Ryan Lamb penalties handed Saints a 6-0 lead and that would have been extended further had Tom Williams' timely intervention not prevented Tom Wood gathering in Samu Manoa's pass for the first try.
But Saints did score when Ben Foden fended off full-back rival Mike Brown to go over in the right-hand corner for a well-taken try.
A strong run from Chris Robshaw set up the platform for Harlequins' first and only points of the night which came through a Rory Clegg penalty.
But Lamb kicked a drop goal shortly after Nick Easter returned from the sin-bin to hand Saints a 17-3 interval lead.
Saints safely negotiated a sin-binning of their own as they continued to boss the second half, and their only disappointment would have been their inability to score more than the one try they managed after the break.
That came from number eight Roger Wilson when the Irishman strolled over the line after Lee Dickson, another strong performer on the night, got quick ball away from the base of the ruck to find Lamb whose distribution skills did the rest.
Lamb landed the conversion to put the final nail in the coffin of league leaders Harlequins.
Tries: Foden, Wilson
Pens: Lamb 3
Yellow card: Easter ( Harlequins - 20th min)
Northampton: 15 Ben Foden, 14 Chris Ashton, 13 George Pisi, 12 James Downey, 11 Noah Cato, 10 Ryan Lamb, 9 Lee Dickson, 8 Roger Wilson, 7 Tom Wood, 6 Phil Dowson, 5 Mark Sorenson, 4 Samu Manoa, 3 Paul Doran Jones, 2 Dylan Hartley (c), 1 Soane Tonga'uiha.
Replacements: 16 Mike Haywood, 17 Alex Waller, 18 Brian Mujati, 19 Christian Day, 20 Ben Nutley / Calum Clark, 21 Martin Roberts, 22 Stephen Myler, 23 Tom May.
Harlequins: 15 Mike Brown, 14 Tom Williams, 13 Matt Hopper, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Rory Clegg, 9 Danny Care, 8 Nick Easter, 7 Luke Wallace, 6 Chris Robshaw (c), 5 George Robson, 4 Olly Kohn, 3 James Johnston, 2 Chris Brooker, 1 Joe Marler.
Replacements: 16 Joe Gray, 17 Mark Lambert, 18 Tim Fairbrother, 19 Tomas Vallejos, 20 Tom Guest, 21 Richard Bolt, 22 Benjamin Urdapilleta, 23 Sam Smith
Venue: Franklin's Gardens
Referee: Dave Pearson