Preston's Graham Alexander with an injury-time equaliser at Charlton.
League One champions Charlton had a 2-0 lead at the break after Danny Haynes fired them in front after Preston failed to clear their lines.
On-loan Dany N'Guessan struck a second after capitalising on more sloppy play.
But Nicky Hunt cut the deficit in half with a stunning volley from 25 yards and Alexander completed a dramatic comeback with a curling free kick.
VIEWS FROM THE DRESSING ROOM:
Preston defender Graham Alexander told BBC Radio Lancashire:
"Never in my wildest dreams did I think I'd do that.
"The free-kick was given, I just jogged up to it and I was going to take it, no matter what.
"I was as nervous as I was when I made my debut at 19 because it was such a big thing for me to stop playing football.
"To be given this chance to say thank you and goodbye everyone, hopefully I've repaid everyone with the goal."
Charlton manager Chris Powell tells BBC London 94.9:
"It was an entertaining game - we set off well and I think we were deserving leaders at half time.
"But I think we took a step back in the second half and we gave them the chance to push on and get back into it.
"I was desperately wanting a win, but where we are and what we have done, I can just about take the draw.
"A 100 points would have been nice for the club, a great accolade but we were pegged back by Preston.
"It is one of the days I can just about stomach being two nil up and then drawing but normally I wouldn't be so happy."