Nahki Wells and his Championship Huddersfield teammates frustrated Manchester City to take their FA Cup fifth-round tie to a replay with a goalless draw at the John Smith's Stadium.
Huddersfield had a first-half strike disallowed for offside and City's Claudio Bravo was the busier of the two goalkeepers as David Wagner's men produced a spirited display.
But City were not overly troubled and given the addition to their fixture lists, both managers might have been left rueing making 15 changes between them.
Rai Simons and his Chesterfield teammates relegation fears deepened when they were beaten 2-1 at home by fellow strugglers Bury and had defender Tom Anderson sent off in a dramatic finale.
Kristian Dennis gave Chesterfield a first-half lead, but after Thorsten Stuckmann had saved Ryan Lowe's penalty, Andrew Tutte equalised with a stunning strike before a terrible blunder by the goalkeeper gave George Miller the chance to seal Bury's first away win since late September.
Reggie Lambe struck the winner in a 2-1 victory for Carlisle at Wycombe that consolidated their automatic promotion place in League Two.
Carlisle, who remain third despite having manager Keith Curle sent off from the dugout late on, are now five points clear of fourth-placed Luton, but it is three defeats in a row for Wycombe, who drop to ninth.
After Adebayo Akinfenwa glanced a header into the bottom corner to give Wycombe the lead, Carlisle quickly hit back when Jamie Proctor was found in space by Lambe and the on-loan Bolton striker picked his spot from the edge of the area.
Route one then led to the Cumbrians taking the lead on 34 minutes, as Mark Gillespie's free-kick was flicked on by Proctor and Lambe was then able to poke the ball past Jamal Blackman.