Town had to settle for a draw at a blustery Butlin Road against fellow promotion contenders, with Rangers' skipper David Jones-Burton's 87th minute header cancelling out Danico Johnson's goal for the hosts earlier in the half.
Whilst it was disappointing that Valley lost their 100% home league record, few would argue that the Lincolnshire visitors did not deserve their share of the spoils, and for the second match running Rugby lacked the dominance that they have generally displayed this season on home territory.
Town boss Carl Adams had made three changes to the starting line-up from their last outing at home to Rothwell, with Dom Perkins, Stefan Blake and Simeon Tulloch in for Josh Steele, Lewis Rankin and Charlie Evans.
The windy conditions made life difficult for both sets of players throughout, but it was arguably the visitors that looked the better side in the opening exchanges.
However the first chance of the game fell to Town on eight minutes, when Johnson curled one wide from the edge of the penalty area.
Danny Jarvis nearly capitalised on a wayward backpass by Loyiso Recci shortly after at the other end, but Rugby keeper Matt Hill illegally halted the Deeping man - and then Danny Schiavi put the resulting free-kick into the Town wall.
Jarvis dragged a further chance wide, with Rugby's Lewis Hayden flashing in a dangerous cross and Keenah Rosser's long range effort forcing Hill's opposite number Lewis Elsom to punch clear.
The final opportunity of the opening period saw Luke Anderson head Schiavi's corner wide.
The strength of the wind intensified after the interval, but there was also a notable improvement to Valley's game, and this was soon rewarded when half-time substitute Evans made an instant impact by playing in Johnson down the left channel - before the striker cut in to fire the ball past Elson into the far corner of the net.
Deeping responded well to the setback and Recci headed a dangerous cross away at the near post, with Schiavi troubling the Town defence with a series of well-delivered corners.
Rugby were now creating chances of their own too though, and Richard Blythe and Evans both just failed to finish off a goalmouth scramble, with Evans then twice almost unlocking the away defence with teasing deliveries from a wide position.
Johnson then blazed his effort over the bar and Perkins tried his luck from distance - with Hill doing well to tip away a cross from Henry Dunn that swirled awkwardly in the wind.
Valley could have sealed the game when Blythe found some space in the Rangers' box, but Elsom did well to block the midfielder's shot with his legs - with Evans blazing the loose ball over the target.
Meanwhile the impressive Schiavi was continuing to trouble Town with his set-piece execution, so it was no surprise when one of these picked out the head of Jones-Burton - who gave Hill no chance from close range to equalise.
Harry Holloway had a shot blocked in the box almost straight from the restart, but Deeping went the closest to a winner when Jonny Lockie got in behind the Rugby defence only to skew his effort wide.
Line-up: Hill; Rosser, Perkins (Rankin), Recci, Francis; Hayden, Blythe, Blake (Evans); Koriya, Tulloch (Holloway), Johnson. Subs not used: Kavanagh, Marsden. Booked: Hill, Hayden.
Deeping line-up: Elsom, Flack, Fryett, Jones-Burton, Hunnings, Anderson, Dunn, Coulson, Mooney, Schiavi, Jarvis. Subs: Lockie, Simpson, Moyo, Carter, Bircham.