Prosser's late winner came after both teams had seen their earlier goalscorers sent off.
Meanwhile, Ryan Bowman, whose low 16-yard shot had brought York back level two minutes before Hurst's red card, was also dismissed by referee Darren Sheldrake four minutes from time for a mistimed lunge.
Southend then made that dismissal count just seconds from the end when Prosser rose high to nod his second goal of the season into the bottom left-hand corner of the net from six yards.
- Sports & Recreation
- Kevan Hurst