Brentford kept up the pressure on Sky Bet League One Leaders Wolves as they beat Crawley 1-0 on Tuesday night.
Jonathan Douglas headed the only goal of the game in the 58th minute as the Bees moved just three points behind Wolves and nine clear of third-placed Rotherham after they slipped up at Sheffield United.
The Blades claimed a 1-0 win over their south Yorkshire rivals after Ben Davies struck a 90th-minute penalty.
In the evening's other game, Peterborough boosted their own play-off hopes with a 2-0 win over Gillingham.
Britt Assombalonga opened the scoring in the 42nd minute before Tommy Rowe added a second which sees Posh go six points clear of MK Dons, who are in seventh place.