Northampton ran five unanswered tries past a below-strength Castres side on Sunday to win 45-0 in the Heineken Cup at Franklin's Gardens.
There was little between the sides during a nip-and-tuck opening 40 and it wasn't until the final quarter of the match that the contest sprung into life.
Pierre Bernard missed the opportunity to give Castres the lead early in the match when he was off target with a penalty from wide on the left.
Northampton's Stephen Myler made the French outfit pay for their miss minutes later when he booted over after the visitors had been caught offside.
The Saints enjoyed the lion's share of possession and territory for the remainder of the half but were unable to add to their advantage.
They had a try ruled out by the video referee after Alex Waller had drove over the line.
Northampton added to their lead in the minutes following the restart courtesy of three further Myler penalties.
The cross-coder was unerring with the boot as Castres struggled to keep their discipline, but the decisive period of the match came at the beginning of the final quarter, as Northampton scored three tries to kill the game as a contest.
First, on 62 minutes, Ben Foden darted over for a converted try to make it 19-0, before Vasely Artemiev and Mike Haywood got in on the act and crossed within minutes of one another.
Myler was on target both times with the boot, making it 33-0 with just ten minutes remaining, but there was still time for Northampton to add to Castres' misery, with a try from Greg Tonks and Haywood's second rubbing salt in to the wounds.
Tries: Foden 2, Artemyev, Haywood, Tonks
Cons: Myler 4
Pens: Myler 4
Yellow card: Roussel (Castres - 21st min)
Northampton Saints: 15 Ben Foden, 14 Vas Artemyev, 13 Jon Clarke, 12 James Downey, 11 Jamie Elliott, 10 Steve Myler, 9 Martin Roberts, 8 Samu Manoa, 7 Ben Nutley, 6 Tom Wood, 5 Mark Sorenson, 4 Courtney Lawes, 3 Paul Doran-Jones, 2 Dylan Hartley, 1 Alex Waller.
Replacements: 16 Mikey Haywood, 17 Soane Tonga'uiha, 18 Tom Mercey, 19 James Craig, 20 James Ingle, 21 Lee Dickson, 22 Greig Tonks, 23 Scott Armstrong.
Castres Olympique: 15 Florian Denos, 14 Matthieu Nicolas, 13 Paul Bonnefond, 12 Pierre-Manuel Garcia, 11 Pierre-Gilles Lakafia, 10 Pierre Bernard, 9 Thierry Lacrampe, 8 Jannie Bornman, 7 Steve Malonga, 6 Pierre Roussel, 5 Scott Murray, 4 Matthias Rolland, 3 Rossouw Kruger, 2 Mathieu Bonello, 1 Anton Peikrishvili.
Replacements: 16 Marc-Antoine Rallier, 17 Michaël Coetzee, 18 Luc Ducalcon, 19 Rodrigo Capo Ortega, 20 Ibrahim Diarra, 21 Rory Kockott, 22 Seremaia Bai, 23 Vincent Inigo.
Venue: Franklin's Gardens, Northampton
Referee: George Clancy