The Pompey players produced a battling display against the U’s after seeing Joe Morrell sent off on 16 minutes for a foul on Cameron Brannagan.
Moment earlier, Michael Jacobs cancelled out Luke McNally’s seventh-minute opener.
And after Ronan Curtis had given the 10-men Blues a 51st-minute lead, Blue hearts were broken when the hosts scored an equaliser eight minutes from time through Brannagan, before Nathan Holland got the winner six minutes into injury time.
9. Michael Jacobs - 9
Involved in both goals and looked the class act he is. Photo: JPIMedia
10. George Hirst - 7
(Replaced by Aiden O'Brien on 83 minutes): Ran himself into ground up front and did superbly to keep hold of ball. Photo: The News
11. Ronan Curtis - 8
Relishes a battle and dug right in, plus great attacking quality. Photo: The News
12. Clark Robertson - 7
(Replaced Kieron Freeman on 60 minutes): Helped Blues try to keep hosts at bay. Photo: JPIMedia