An improved second half display saw Town ultimately secure a comfortable victory over their spirited opponents.
Lee Thomas broke his Valley duck with a goal either side of half-time, with Dan White also on-target for the first time in a Town shirt since his move to the club in the summer.
With Kieran Fitzgerald unavailable, the inclusion of Thomas in an unfamiliar advanced role was the only change from the previous weekend's thrilling FA Cup defeat at Sporting Khalsa.
The visitors shaded the opening exchanges, with Rugby keeper Matt Hill doing well to beat away a Jordan Nelson shot and Ryan Calver blazing one way over the bar.
Town were struggling to make any meaningful incursions, with a dangerous Charlie Evans cross after neat skill from Justin Marsden their only foray into the Nirvana box in the opening half an hour.
However the dismissal of Leicester's Rahul Parmar for a needless late tackle on Caine Elliott near the corner of the pitch then gave the hosts a numerical advantage for the remainder of the game.
Jamal Clarke headed Ryan Seal's free-kick wide, ahead of the opening goal which again came via a Seal assist when he picked out Thomas with a searching crossfield pass. Thomas then twisted his marker inside and out before firing the ball past Michael Antkowiak into the roof of the net.
Deen Master powered a free-kick just wide for the visitors just before a generally uninspiring first half was ended by the referee's whistle.
Thomas was again too good for his full-back shortly after the restart, but his cross into the penalty area was blocked out.
Another good chance for Rugby followed shortly after when Evans had a shot headed off the line, after another long pass by Seal was helped onto him by Thomas.
Master was again just off-target from the edge of the area, before Thomas made it two nil with a simple finish after Marsden had seized upon a defensive mistake to surge to the byline and steer the ball across the face of the goal.
With the added goal cushion, Valley then took control of the game and a number of good chances followed.
Dan Kavanagh blazed over and Seal almost helped himself to what would have been a deserved goal, before White rose highest to head home a Thomas corner just beyond the hour mark.
Sub Harry Holloway struck one wide and Thomas smashed a hat-trick attempt into the back of the stands from a threatening position, with Seal having two further efforts on goal as the game drew to a close.
Hill denied Ishmael Ajdaa with a good save and fellow sub Aboubacar Cisse also dragged one wide, as Nirvana looked for a late consolation.
Line-up: Hill; L Recci, Kavanagh, Clarke (O Recci), Alexander; Elliott (Holloway), White, Seal; Thomas, Evans, Marsden (Lockley). Subs not used: Francis, Padmore. Booked: L Recci.