Valley came up agonisingly short again despite a good performance at promotion hopefuls Loughborough Dynamo.
Rugby were made to pay for their defensive errors and for a second away game in a row striker Jordan Wilson had to play in goal for the whole second half after goalkeeper Tomasz Bukowski withdrew with injury.
Town were without the injured Josh Thomas and the suspended Ryan Sahota for the trip to Leicestershire - meaning a first start for young Devonn O'Sullivan in midfield and a club debut for the newly-signed Jamie Melbourne at full-back.
Valley started brightly enough, and the first real chance fell to them after O'Sullivan had purposefully driven into the Dynamo box to tee up Michael Taylor for a shot that was kept out by a sprawling save from Lewis King - with the home keeper also blocking Taylor's follow-up attempt with his ample frame.
Dan Summerfield then did well to clear a dangerous cross from Rio Molyneaux, before a George Ball put in an effort from the edge of the box which always missing the target.
Ball shot another one straight at Bukowski, with the Town keeper also comfortably gathering Deen Master's strike as the hosts began to assert themselves on the game.
The visitors continued to create opportunities too though, with David Kolodynski releasing O'Sullivan - whose sliding shot was blocked away, and then a looping cross from Kolodynski was headed wide by a stretching Taylor.
Bukowski stopped another Ball effort, before the home side broke the deadlock on 32 minutes after Melbourne was dispossessed on the left-hand side to allow Taylor Anderson to send in a low cross that was ultimately helped home from close range by Molyneaux.
Evan Garnett nearly doubled the margin shortly after, but Bukowski was equal to his attempt from a tight angle.
However, Rugby got themselves level after Summerfield played in Kolodynski to fire one below King and into the net.
A snapshot volley from Garnett was pushed strongly away by Bukowski as the busy end to the half continued, but with Bukowski now struggling with his kicking after picking up a groin injury, Loughborough recycled one such wayward clearance by the Town keeper and from Jonathan White's resulting cross, Ball's flick-on was helped into his own net by Melbourne to give Dynamo a lead at the break.
Valley emerged with Wilson wearing the gloves again, and they were soon on the back foot with Liam Francis doing well with a recovery tackle to thwart Molyneaux and then Mitchell Robinson heading wide the resulting corner.
Robinson did hit the target from a subsequent corner to register Dynamo's third though on 54 minutes, but within five further minutes Rugby were back in the game again when Taylor's bullet header to Clements's inswinging free-kick reduced the arrears once more.
With Wilson looking increasingly assured between the sticks, hopes were boosted that Rugby could go on and grab an equaliser.
A threatening Madundo Semahimbo cross was headed away, with the half-time replacement for Bukowski then almost onto another Clements delivery into the box.
Kolodynski's speculative volley flew way over, with a sliced effort from Semahimbo then almost falling nicely for Taylor.
At the other end, Melbourne somehow blocked a Garnett effort from a couple of yards out and Master's well-struck free-kick clipped the angle of the woodwork, with a further chip from Garnett drifting wide.
Semahimbo's wild strike from distance failed to trouble King, before he then headed one at Lewis after he had followed-up on his own blocked cross.
The final significant opportunity of the match also fell to the visitors, with Loyiso Recci heading over Clements's corner to the back post.
