Spurs go to Brammall Lane with a narrow One Nil victory against the Blades in their first leg Capital One Cup semi-final.
Andros Townsend scored a penalty in the only goal of the game.
He converted after the ball was handled in the Sheffield penalty area.
Jeers could be heard when Emmanuel Adebayor was substituted in the second half.
If Spurs survive the second leg next Wednesday they play the winners of the other semi-final between Liverpool and Chelsea.
Mauricio Pochettino siad ‘It was a tough game. Now we go to Sheffield with a victory but it will be tough up there.’