Neill Collins' first goal for Sheffield United saw off promotion rivals Huddersfield Town to move the Blades up to second in League One.
The former Wolves defender gave the visitors a fifth-minute lead, heading in unmarked inside the six-yard box.
Jordan Rhodes went close to levelling for the Terriers just before half-time when he struck the post with a volley.
Skipper Michael Doyle cleared Sean Morrison's goal-bound header off the line as the visitors held on.
The win moves the Blades above city rivals Sheffield Wednesday, who lost 1-0 at home to Stevenage.
It was only the third league defeat of the season for Lee Clark's Huddersfield, who stay fourth.
VIEW FROM THE DRESSING ROOM
Blades manager Danny Wilson told BBC Radio Sheffield:
"It was a fantastic game. We had some terrific football from both sides, we've had chances from both sides, we've seen some fantastic goalkeeping. And, thankfully, from our point of view, we've got the all important goal.
"It was one of those games where we could have won it, we could have lost it, we could have drawn it, but thankfully we've managed to see it through.
"We had some immense defending at times and we had to do. That ball was raining in our box from long throws and free kicks etc and you could have to put your body on the line."