Substitute Tom Soares grabbed an extra-time winner for Crystal Palace as they avoided a shock Carling Cup exit.
Palace went behind on 70 minutes when Hartlepool substitute Eifion Williams slotted home after Gabor Kiraly failed to hold Mike Nelson's shot.
After a string of misses, Dougie Freedman finally scored 10 minutes later to force extra time.
And Soares completed the comeback when he lashed home Danny Granville's knock-down after 110 minutes.
Crystal Palace: Kiraly, Granville, Powell, Sorondo (Borrowdale 88), Boyce, Routledge, Derry (Soares 76), Watson, Kolkka, Freedman, Torghelle (Kaviedes 61).
Subs Not Used: Speroni, Togwell.
Booked: Sorondo, Kolkka.
Goals: Freedman 80, Soares 110.
Hartlepool: Provett, Robson, Tinkler, Nelson, Westwood, Humphreys, Strachan (Maidens 86), Sweeney, Woods (Istead 105), Boyd, Porter (Williams 55).
Subs Not Used: Konstantopoulos, Craddock.
Goals: Williams 70.
Ref: K Wright (Cambridgeshire).