The 'Irons' had taken the lead through a Fabian Balbuena header, and looked to be in the driving seat in the game as a result.
However, all that changed in the 38th minute when Mark Noble made a heavy touch in the middle of the park.
The experienced midfielder looked to rectify the error, and stop Ndidi from taking posession of the ball, by sliding in to win it back. His studs were raised and he did not make contact with the ball, instead clattering in to the ankle of the Nigerian midfielder.
Referee Michael Oliver had no hesitation, having been in the perfect position to witness the incident, and reached for his red card, much to the surprise of Noble and his West Ham colleagues.