A 37-0 victory over Edinburgh at Franklin's Gardens on Friday allowed Northampton to finish top of Pool One and book themselves a place in the Heineken Cup quarter-finals.
The Saints made it five wins from five matches to top Pool One, but they failed to ignite the Franklin's Gardens crowd until the closing stages of an error-strewn contest as Paul Diggin scored three late tries and four in all.
An emphatic win looked to be on the cards when prop Brian Mujati touched down in the third minute after a drive by the Northampton pack following a lineout.
Stephen Myler added the conversion and a 16th-minute penalty before Diggin squeezed over for a second Saints try in the left-hand corner on the half-hour.
Myler missed his conversion attempt, while Chris Paterson and David Blair were off-target with penalties for the visitors, who rarely troubled the home defence.
Another penalty from Myler made it 18-0 shortly after the break, but Northampton then struggled to break through until Ben Foden sent Diggin charging down the left wing for his second try on 72.
That woke the crowd from their slumbers and they were roaring again when Foden played in Joe Ansbro who unselfishly passed to Diggin to complete his hat-trick.
That gave the Saints a bonus point which could ensure a home tie in the last eight and there was still time for Diggin to touch down yet again at the death.
Tries: Mujati, Diggin 4
Cons: Myler 3
Pens: Myler 2
Northampton: 15 Ben Foden, 14 Joe Ansbro, 13 Jon Clarke, 12 James Downey, 11 Paul Diggin, 10 Stephen Myler, 9 Ryan Powell, 8 Roger Wilson, 7 Tom Wood, 6 Phil Dowson, 5 Christian Day, 4 Calum Clark, 3 Brian Mujati, 2 Dylan Hartley (c), 1 Soane Tonga'uiha.
Replacements: 16 Brett Sharman, 17 Alex Waller, 18 Tom Mercey, 19 Mark Sorenson, 20 Mark Easter, 21 Stuart Commins, 22 Joe Ford, 23 Bruce Reihana.
Edinburgh: 15 Chris Paterson, 14 Jim Thompson, 13 Ben Cairns, 12 Nick De Luca, 11 Tim Visser, 10 David Blair, 9 Mike Blair, 8 Roddy Grant (c), 7 Ross Rennie, 6 Alan MacDonald, 5 Esteban Lozada, 4 Scott MacLeod, 3 Geoff Cross, 2 Ross Ford, 1 Kyle Traynor.
Replacements: 16 TBC, 17 Lewis Niven, 18 David Young, 19 Craig Hamilton, 20 Stuart McInally, 21 Greig Laidlaw, 22 James King, 23 Simon Webster.
Referee: Christophe Berdos (France)