It would be no surprise were Castres' coaches, Laurent Labit and Laurent Travers, to name a similar team when they lock horns with the Saints in the Heineken Cup in December.
So while it was disappointing to see Paul Diggin leave the fray with just over a minute on the clock, it was a great opportunity for 17-year-old Tom Collins to compare himself against one of the best teams in France.
Castres made the most of their considerable experience by scoring through Marc Andreu, the international winger wrong-footing Anders Mogensen on the home right. Scrum-half Rory Kockott's conversion made it 7-0, but although the big Castres pack tried to give their backs a platform to attack from deep by turning free kicks into scrums on their own the black, green and gold defence stood firm. So positive was the defence that a penalty was awarded from which Ryan Lamb got his team on the board.
Having fallen behind so early Saints were doing well to maintain their structure, Greig Tonks sending a good kick to the home line and Lamb unlucky when a good looking spiral bounced long and over the dead ball line.
The heat and pace were certainly taking their toll on the home players more than Castres, whose Top 14 campaign begins next weekend against Perpignan. But while plenty of the forwards were blowing and taking their time to get back into wide positions, Andreu was looking sharp, his chip and chase forcing Collins to concede a five-metre scrum.
The 20-minute drinks break certainly came at the right time for Castres, and their pack gathered themselves to put on the pressure at the set piece. So it was very much to their credit that Saints stood firm, gang-tackling Thomas Sanchou into touch and winning a penalty at the lineout to clear their lines.
Saints also had a spell of promising possession as the half-hour approached. But unlike Castres they could not make the most of the visit to the red zone, and when Andreu darted over for his second try Castres had an 11-point lead.
Andreu also set up his side's third try of the night, scored by Thomas Sanchou, but the star of the show from Castres' perspective was Sanchou's centre partner, Romain Cabannes, who three times kept the ball alive while being tackled to send team mates through the gap he'd created.
Kockott made it three from three with his conversion, but Lamb was vying for the title of Mr Accurate, too, his two 50-metre penalties adding to his earlier effort to ensure that Saints had the last word of the half for a 21-9 scoreline.
There was promise in the first play after the break, Greig Tonks getting the ball in his hands to make a half-break. Unfortunately it proved to be short lived, Castres winning a penalty at the breakdown and Chris Masoe powering over from the resultant lineout.
Again Saints came back, Masoe getting a talking to on behalf of his team for some dangerous play and Lamb kicking to the corner. Collins came close to a try, being forced out a couple of metres from the line, but while Saints were coming close it was Castres who were scoring the tries, scrum-half Romain Teulet crossing in the left corner.
Despite conceding those scores Saints were still trying their hardest to stem the tide. But while Castres' were going through their playbook - scoring again before the hour through Rodrigo Capo Ortega - nothing the travellers tried was sticking. The ball went loose while they tried to make the most of a turnover, and a Cesar Sempere pass out of the tackle instead went to an opponent.
Saints' efforts were summed up just after the resumption of play. A nice sidestep from Ben Prescott, a burst through a gap from Lamb and some excellent sleight of hand from Ben Nutley to James Craig were all undone by Castres turning the ball over and kicking long.
If anything the difference between the teams should have been exaggerated in the final quarter. Castres were rolling on the likes of Capo Ortega and Teulet, while Saints were giving teenagers like Jamie Warr and Jordan Husband a run out. But the youngsters were not overawed, holding the seasoned campaigners out and scaring them with some attacks from deep.
But the game had long gone by that point, and although there were some final forays into the home 22 Castres had the win in the bag.
4mins CASTRES Try Andreu Con Kockott 7-0
12mins SAINTS Pen Lamb 7-3
31mins CASTRES Try Andreu Con Kockott 14-3
35mins SAINTS Pen Lamb 14-6
38mins CASTRES Try Sanchou Con Kockott 21-6
40mins SAINTS Pen Lamb 21-9
HALF-TIME CASTRES 21 SAINTS 9
42mins CASTRES Try Masoe 26-9
49mins CASTRES Try Teulet 31-9
53mins CASTRES Yellow card Caballero
58mins CASTRES Try Capo Ortega Con Teulet 38-9
FULL-TIME CASTRES 38 SAINTS 9