Valley put in perhaps their worst performance of the season as they fell to a home defeat against Cogenhoe United.
Whilst the visitors were good value for their win, this was generally a forgettable encounter - and at times unwatchable - as Rugby failed to create a single real chance of note throughout.
Valley were unchanged from the previous weekend's victory at Boston against a youthful looking United line-up.
A Dom Perkins' header into the penalty area was just out of the reach of team-mate Simeon Tulloch in a rare moment of early promise from Town, with the majority of the first half opportunities coming the way of the away side.
The first of these saw Joe Mellings toe a free-kick by Tom Iaciofano over the bar, with Jack O'Connor's rising half-volley then caught by Louis Connor.
Calamitous defending between Dan Summerfield, Justin Marsden and Perkins presented Sean McBride with a strike - which Connor was again equal to, whilst O'Connor also headed one off-target.
Valley's only shot of the opening 45 minutes came when Summerfield failed to extend United's teenage keeper Zac Cunningham with his effort from the edge of the area.
After the restart, Cunningham easily gathered Tulloch's left footed strike after Edwin Ahenkorah had played him in, and even the introduction of Town's leading scorer in the league Lewis Rankin just ahead of the hour mark could not spark Carl Adams's men.
Cogenhoe were then denied what looked to be a stonewall penalty when McBride appeared to have been tripped in the box by Josh Steele, but after consultation with his assistant, the match referee Paul Gregory controversially decided that the United player had dived.
The visitors did not have to wait long to get their just reward though, after Connor had executed a fine double save to twice deny their skipper Matt Long - first getting down well to parry his effort and then smothering his follow-up attempt away for a corner.
However Connor switched from hero to villain when he missed the subsequent set-piece inswinging delivery from Long - leaving an unmarked Lowery to sweep the ball home with ease.
United went on to have a number of good chances to increase their margin of victory, with McBride lifting one over the bar after he was clean through on the counter, and Long also guilty of the same after Montel Dore had stormed through the middle of the Town defence.
Rugby's miserable afternoon was summed up by two events late on, with Tulloch finding the roof of the stand with his strike and Summerfield dismissed in stoppage time after receiving his second yellow card of the game.
Line-up: Connor; Rosser, Steele, Recci, Summerfield, Perkins, Marsden (Kavanagh), Holloway (Rankin); Tulloch, Evans, Ahenkorah. Subs not used: Dawson, Francis, Hill. Booked: Perkins, Summerfield. Sent Off: Summerfield.
Cogenhoe line-up: Cunningham, Lowery, Iaciofano, O'Connor, Barwell, Stevenson, Melling, McBride, Long, Dore, Slinn. Subs: Jarvis, Shanley, I'Anson, Drinkwater.