If this was the night when Tottenham Hotspur's schedule caught up with them, when they found their well-trained legs tiring, they still just about kept their long season on course.
auricio Pochettino will have wanted far more than a 1-0 lead to take to Bramall Lane for the second leg of this League Cup semi-final match.
Spurs wanted to kill this tie last night, to impose themselves on their League One opponents and ensure that they could spend the next few days making their arrangements for the Wembley final on March 1. Instead, they face a searching test in the second leg.
Nigel Clough's side were late arriving to White Hart Lane but they played the whole match as if they were making up for lost time. The visitors matched Spurs run for run, tackle for tackle and, for all of the hard physical work Pochettino has put into his players, they looked more tired than they had done all season.
This was their sixth game this month, and they have another three left. It is starting to show.
These are the games, in mid-week, in the cups, against lesser opposition, when Pochettino knows that he needs to rotate his squad.
Last night he brought Emmanuel Adebayor in for his first start since November.
Adebayor rewarded his manager with one yellow card and one missed chance in 64 disappointing minutes.
His replacement, Roberto Soldado, was warmly received, more involved and helped to win the penalty, which Andros Townsend scored.
It was far less than Spurs wanted but probably more than they deserved. Sheffield United, competitive, compact and courageous, arguably made the better chances in open play. They will, of course, have to win the second leg at home next week but if they play this well again that is far from inconceivable.
Spurs had been warned in advance that the Premier League was too "matey matey", that Sheffield United would kick them and that they would not like it. This was not empty talk as the visitors, even after their long delay in reaching White Hart Lane, began with a ferocious onslaught on their presitigious hosts.
Mauricio Pochettino is associated with brisk, direct, pressing football but his side, for the first 20 minutes, were outrun by the League One side.
Their only first-half chance in open play fell to Adebayor but he looked like a player whose last goal was in October as he shot over.
Tottenham resumed after the break with a marginally better tempo, trying, with varying success, to get in behind their troublesome visitors. Townsend started to test defender Bob Harris but the United players were proving just as indefatigable as their thousands of travelling fans, unwilling to let their early spirit and passion fade.
Adebayor received smatterings of boos as he departed, having done little in his 64 minutes of football to suggest that Pochettino ought to have picked him more often.
Soldado has, despite everything, retained the support of most of the home fans, and he applied himself from the start.
It was not exactly what he was bought for - Soldado is meant to be a ruthless finisher - but it was that hard work that opened the game for Spurs.
Jan Vertonghen clipped a ball into the channel which Soldado ran down. Jay McEveley, perfect until then, panicked and stuck his hand out. Neil Swarbrick awarded the penalty and Townsend put it into the bottom corner.
(© Independent News Service)