Apart from the obvious – a little straight-line speed, a lot of defensive know-how and a kick like a mule – what weapon does a full-back need in his armoury to survive at the top end of the professional game? A sense of timing, that's what.
Happily for Ben Foden, whose World Cup performances in the No 15 shirt did little to suggest his place in the England team was any more rock-solid than Twickenham's ability to keep embarrassing information out of the press, his eye-catching display yesterday caught the moment perfectly, not least because the national side's caretaker coach, Stuart Lancaster, was looking down on him from on high.
If this was not quite a "dead" affair, it was certainly a fixture of the "not feeling terribly well" variety. Northampton were already out of the tournament, having lost three from three, while Castres travelled without a host of front-line players: Marc Andreu, Max Evans and Romain Teulet among the backs; Ibrahim Diarra, Chris Masoe and Joe Tekori among the forwards. Therefore, Lancaster could only have been in the East Midlands – as opposed to Toulouse, say – for very specific reasons pertaining to Six Nations selection and it was perfectly reasonable to suggest Foden was one of them, especially as some of his rival full-backs, Mike Brown of Harlequins and Alex Goode of Saracens to name but two, had been setting tongues wagging.
The coach is known to favour "footballing" full-backs, as opposed to No 15s who run like Usain Bolt while possessing all the distributive skills of a third-team prop with a bad case of butterfingers. Foden is as quick as any No 15 in Europe; indeed, he reminded the 11,000-plus crowd of this when he covered 60-odd metres in the blink of an eye to score his second try with the last attack of a one-sided match, circumnavigating the unfortunate Florian Denos en route. But he was also contributed handsomely to Vasily Artemyev's fine touchdown on 66 minutes with a high-calibre pass out of contact – a classic case of extracting maximum value from minimal opportunit.
Foden's first try, just past the hour, was a more straightforward affair: the teenage wing Jamie Elliott, one of several bright young things to emerge from the Northampton academy, did the hard work with an energetic thrust in centre-field, leaving the fully-fledged international to score unchallenged towards the right flag. But Foden had already made his mark during a tryless – and very nearly pointless – first half with a series of dangerous raids up the left. When he finds himself some space and resists the temptation to kick the ball aimlessly upfield, he remains a significant handful.
"There are quite a number of other full-backs getting good write-ups, but in fairness to Ben he's been outstanding for us since he returned from the World Cup," said Jim Mallinder, the Northampton director of rugby. As Mallinder is not known for talking up his players in public without good reason – given the choice, he would take the Trappist approach to rugby management – it was a meaningful remark.
Castres turned in precisely the kind of performance the Heineken Cup does not need: an understrength side playing undercooked rugby so early in the tournament is never edifying. Given the semi-interested nature of their offering, Northampton's first-half display was a long way short of exhilarating, Stephen Myler's sand-wedge penalty from in front of the sticks on 12 minutes the sole difference between the teams. The Frenchmen lost Pierre Roussel to the sin bin yet still managed to keep their line intact.
Sadly for those who prefer a contest to a procession, they were not up to keeping themselves intact after the interval. Myler's flurry of penalties between the 44th and 51st minutes put the game out of French reach and Foden's opening strike broke the visiting resistance once and for all.
Scorers: Northampton: Tries Foden 2, Artemyev, Haywood, Tonks Conversions Myler 4 Penalties Myler 4.
Northampton: B Foden; V Artemyev, J Clarke (G Tonks, 67), J Downey (S Armstrong, 61), J Elliott; S Myler, M Roberts (L Dickson, 61); A Waller (S Tonga'uiha, 56), D Hartley (capt, M Haywood, 62), P Doran-Jones (T Mercey, 56), C Lawes (J Craig, 51), M Sorenson, T Wood, B Nutley (J Ingle, 63), S Manoa.
Castres: F Denos; M Nicolas (V Inigo, 68), P Bonnefond, P Garcia, P Lakafia; P Bernard, T Lacrampe (R Kockott, 61); A Peikrishvili (L Ducalcon, 52), M Bonello (M-A Rallier, 52), R Kruger (M Coetzee, 45), M Rolland (capt, R Capo Ortega, 68), S Murray, P Roussel, S Malonga, J Bornman (Y Caballero, 43).
Referee G Clancy (Ireland).