Jon Clarke's try on the resumption gave Saints the initiative and JamesDowney crossed on the hour, Myler converting both before another penalty sealed it.
Saints began their task with real purpose, with centre JamesDowney and fly-half Stephen Myler controlling the early ebb and flow from midfield, despite two worrying line-out steals by Castres.
In contrast the Blues chose to boot two difficult penalty chances to touch, the second leading to a sustained assault on the Northampton line that saw Saints centre JamesDowney sent to the sin-bin for killing the ball.
While virtually any radar would have some capability for such space tracking, the inappropriateness of the Krasnoyarsk facility for this purpose was obvious even to individuals untutored in radar technology like Congressmen Tom Downey (D-NY), Bob Carr (D-MI) and James Moody (D-WI).