Sporting Khalsa came from behind to secure a deserved win at Butlin Road.
Valley had taken the lead on sixteen minutes when Justice Campbell scored for the second home game in succession, but the visitors rallied well and ran out deserved winners in the end to secure the double over Carl Adams's side.
Adams had made one change to his starting line-up from the previous outing - a narrow defeat at high-flying Harborough, with skipper Barry Fitzharris returning after completing his recovery from concussion in place of hamstring injury victim David Kolodynski.
The hosts made a bright start, with Josh Thomas firing one off-target from a wide right position.
The opening goal came after a neat pass from Ryan Sahota released Campbell in the Sporting box, and the midfielder completed a smart finish by sliding the ball under the body of Ben Whiting.
Jordan Wilson then headed one wide under pressure after Thomas had swung one in, but that represented Rugby's last real chance of the first half as the visitors found their feet and started to look a threat themselves.
The equaliser came on 32 minutes when the debuting Marvellous Onanbirkhanlen pounced on a rebound to Matt Fulloway's initial strike to score from close range.
Khalsa finished the opening period in buoyant fashion, with Chay Tilt sending a free-kick over the bar and Onanbirkhanlen's effort from a tight angle blocked away - as was a further shot from Robbie Bunn.
Curvin Elllis went closest to establishing an advantage at the interval, but he stabbed the ball wide after Town keeper Tomasz Bukowski had spilled Fulloway's header in the goalmouth. Sporting carried on where they had left after the players returned to the pitch, with Bunn firing a free-kick straight at Bukowski.
The influential Bunn then saw a dangerous corner headed away by Loyiso Recci, with Bukowski also denying him when he pushed away his cross from the left.
In a rare attacking highlight for Valley, Recci's strike following a Campbell free-kick was blocked by a defender, before the visitors somewhat inevitably took the lead on the hour mark when Bunn speared one home after Tilt's free-kick into the area had been laid back to him on the edge.
It was soon three when Dilano Reid's strike from an improbable angle skimmed off the body of James Mace before slipping through the hands of Bukowski.
The home side did show some commendable promise after this double blow though, with newly-signed substitute Devonn O'Sullivan soon marking his introduction onto the pitch with a strike from 25 yards that was gathered by Whiting.
Drew Kear's surge forward ended with a rising shot that was pushed away by Whiting, and then Whiting was down well to keep out Thomas's low effort - after another purposeful run at the Khalsa defence had opened things up.
At the other end Bukowski smothered out Ellis, as the striker bore down on goal and then Bunn's fiercely struck shot was diverted away by a Rugby head.
O'Sullivan sent a further chance wide of the target, with Wilson also seeing a decent opportunity blocked after Sahota's pass had set him up.
The final strike of the game again fell to O'Sullivan, but his half-volley flew marginally over the bar.
Valley
Line-up: Bukowski; Thomas, Summerfield, Mace (Clements), Recci; Lee (O'Sullivan), Fitzharris, Campbell (Kear); Semahimbo, Sahota, Wilson. Subs not used: Francis. Bookings: Sahota, Kear.
