Only four points now separate the Blades and Boro after this 1-0 defeat to the Hatters, thanks to Carlton Morris’ goal early in the second half.
Overall, it was a poor display by Paul Heckingbottom’s side who looked as though they had given the visitors too much respect as the home side and struggled to really get going from the first minute.
Here’s how we rated the Sheffield United players after a miserable day at Bramall Lane
9. Sander Berge - 6
Tried to make things happen in the middle of the park but kept running into blind alleys, not helped by the lack of movement around him Photo: Lexy Ilsley
10. Iliman Ndiaye - 6
Ended up dropping deep in an attempt to make something happen as the poor midfield weren't getting the ball to him. Generally struggled to find a way through a disciplined Luton defence Photo: Michael Regan
11. Oli McBurnie - 6
Given very little service - had a few headers on target but nothing to really cause much trouble. Worked hard but was fighting a losing battle for much of the day Photo: Simon Bellis
12. SUBS: Billy Sharp - 5
Prompted a little bit of an upswing when he came on for Fleck but it didn't last very long. His arrival probably wasn't the right call at the time as United had nothing in midfield at that stage Photo: Andrew Yates