Andros Townsend hits right spot but Sheffield United are still in it
Spurs 1-0 Sheffield United
Much of the focus ahead of this match surrounded two former Sheffield United players within the Tottenham ranks.
Kyle Naughton and Kyle Walker arrived together from the Blades in 2009, although the former was absent ahead of a move to Swansea as England right-back Walker started against his boyhood club.
Walker was cheered from the outset by the visiting supporters, who were in fine voice after making an impressive start to the match, which was delayed by 15 minutes after the United bus got stuck in heavy traffic.
Neither United nor Spurs were able to create clear-cut chances, though, with the only early moment of note seeing appeals for the hosts to be reduced to 10 men.
Nigel Clough and his coaching staff jumped off their seats after Emannuel Adebayor caught Louis Reed's face, although, after some deliberation, referee Neil Swarbrick only dished out a yellow card.
It was a moment that sparked the match into life, with Spurs fan Jamal Campbell-Ryce fizzing a strike across the face of goal before Blades goalkeeper Mark Howard palmed away an Eric Dier header.
That was the north Londoners' only shot on target during a tense first half, although Adebayor should have tested Howard after impressively bringing down a floated Christian Eriksen ball, only to flash over under pressure.
Dier's header wide in stoppage time was Spurs' only other effort of note before half time, and they came close to going into the break behind as Stefan Scougall fired just wide after Ben Davies sloppily gave away possession.
United returned from the interval with the same intensity, but were making an increasing number of mistakes.
Fortunately for Clough's men, Tottenham could not capitalise as they struggled to break down the League One side.
That lack of cutting edge saw Mauricio Pochettino make a double change with 25 minutes remaining, with Mousa Dembele and Roberto Soldado replacing Ryan Mason and Adebayor, who was booed by some Spurs fans for the second match in succession on a night he captained the side.
It did not take long for those alterations to have the desired effect, with Harry Kane freed up to take a shot blocked by Chris Basham, before Soldado earned a 74th minute penalty.
Jan Vertonghen clipped a diagonal ball to the Spain international and Jay McEveley, who had been swinging his arm around claiming offside, clumsily handled.
Andros Townsend stepped up for the resulting spot-kick and, while it was far from a perfect penalty, it beat Howard low to his left.
United pushed for a late leveller but substitute Jose Baxter failed to test Michel Vorm and Jamie Murphy fired wide after a tame Paulinho attempt at the other end.