Sheffield United moved within two points to the championship automatic promotion slots and won the 10-man Middlesbrough in Bramall Lane.
Richard Stearman made a free-kick for Oliver Norwood to give the Blades the lead one minute after Billy Sharp's goal.
Boro's night ended badly four minutes later as center-back Daniel Ayala was sent off for two yellow cards within seven minutes.
Substitute Britt Assombalonga had the best chance of taking Boro to a new level, but Dean Henderson saved his legs after the striker scored the goal.
Third-placed Blades is approaching second-placed Norwich, who lost the lead to second place following a 3-1 victory at Preston following Leeds' win over Swansea City.
Both goalies marked the climax of an uneventful first half – Boros Darren Randolph made a fantastic one-handed shot from Mark Duffy's excellent shot in six minutes before Henderson sent Jordan Hugill past the post.
Almost five minutes into the restart, the guests took the lead when George Friend cleared Enda Stevens' header from the line.
Half-time substitute Gary Madine had two penalties just before Stearman's goal when Boro missed the chance to reach fifth place in Bristol City.
Sheffield United manager Chris Wilder told BBC Radio Sheffield:
"It was a good three points, a big win after what happened on Friday (3-0 lead at Aston Villa), so we're happy.
"We had to mix the rudder a bit and it was not as smooth as we expected, but it was still a balanced game in the first half.
"There are different ways to win football matches, we try to play through teams, if not we have to go over the top and be a bit more direct against the front line team, we did that in the second half and I thought I worked a pleasure. "
Tony Pulis, manager at Middlesbrough, told BBC Radio Tees:
I'm really disappointed with the goal, I think the line manager's decision to play a free-kick is shocking, and if they give it a free kick, the boy who scores the goal has knocked and jumped Dael (Fry) and the referee in a great position to give it and does not exist, it's a free kick every single minute of the day.
"It was such a big game tonight and we have a referee who has played just eight games in the championship all season.
"You look around and you have other referees who run and drop Premier League games – that's not the referee's fault, it's the person in charge, and that can not be right, that's not good enough."