Castres made a statement of intent when they beat Northampton 41-7 in their Champions Cup clash at the Stade Pierre Antoine on Saturday.
The hosts were excellent in the opening period and deserved the 20-0 advantage they built via David Smith and Antoine Tichit tries, while Benjamin Urdapilleta kicked 10 points from the tee.
Smith added his second before James Wilson gained the Midlanders some consolation, but Alexandre Bias and Antoine Dupont touched down late on to seal the bonus-point win.
Against a Northampton side shorn of Luther Burrell and George Pisi in the centre, the French outfit'?s direct approach paid dividends early on.
They dominated the collisions and, under pressure, the visitors conceded a penalty which was converted from long range by Urdapilleta. The fly-half was also on target minutes later as Castres continued to control possession before the Premiership team finally found some territory.
This time it was the hosts who consistently infringed and that led to a yellow card for Rory Kockott. Despite being up a man, the Englishmen struggled to break through and it was the Top 14 club that scored the first try.
Alex Tulou, who was a threat in the first half, broke through the heart of the opposition defence and off-loaded to Smith to touch down. Jim Mallinder's men were struggling to deal with Castres' sheer power and that was demonstrated when another turnover led to a second try.
After Kockott had collected a chip kick, the home side went through the phases and Tichit eventually crossed the whitewash for a 20-0 lead at half-time.
Northampton's pain continued in the second period and Smith immediately put the result beyond doubt four minutes into the half.
Although the Saints battled and reduced the arrears through Wilson, Bias scampered over for the bonus-point effort. With the Midlanders now disconsolate, the French side completed the win when Dupont touched down.
Tries: Smith 2, Tichit, Bias, Dupont
Cons: Urdapilleta 3, Dumora
Pens: Urdapilleta 2
Yellow Card: Kockott
Castres: 15 Geoffrey Palis, 14 Horacio Agulla, 13 Thomas Combezou, 12 Robert Ebersohn, 11 David Smith, 10 Benjamin Urdapilleta, 9 Rory Kockott, 8 Alex Tulou, 7 Anthony Jelonch, 6 Mathieu Babillot, 5 Victor Moreaux, 4 Loic Jacquet, 3 Daniel Kotze, 2 Jody Jenneker, 1 Antoine Tichit
Replacements: 16 Brice Mach, 17 Mihaita Lazar, 18 Yohan Montes, 19 Thibault Lassale, 20 Alexandre Bias, 21 Antoine Dupont, 22 Julien Dumora, 23 Florian Vialelle
Northampton: 15 Ben Foden, 14 James Wilson, 13 Rory Hutchinson, 12 Harry Mallinder, 11 George North, 10 Steve Myler, 9 Nic Groom, 8 Louis Picamoles, 7 Teimana Harrison, 6 Tom Wood, 5 Michael Paterson, 4 Courtney Lawes, 3 Kieran Brookes, 2 Dylan Hartley, 1 Alex Waller
Replacements: 16 Mikey Haywood, 17 Ethan Waller, 18 Paul Hill, 19 Api Ratuniyarawa, 20 Jamie Gibson, 21 Lee Dickson, 22 Nafi Tuitavake, 23 Ahsee Tuala
Referee: Ian Davies (Wales)
Assistant Referees: Simon Rees (Wales), Robert Price (Wales)
TMO: Gareth Simmonds (Wales)