Garry Monk was sacked by Middlesbrough chairman Steve Gibson despite the pair holding a meeting only on Wednesday in which they made plans and identified targets for the January transfer window.
During the meeting, the Middlesbrough board gave no indication that they intended to relieve Monk from his position.
Monk oversaw a 2-1 comeback victory at Sheffield Wednesday on Saturday to lift Middlesbrough to within three points of the play-off places.
However, the manager was left devastated as he received a phone call upon arriving at his home near Teesside shortly after 8pm.