Visitors Posh looked certain to seal all three points thanks to goals either side of the break from Gwion Edwards and Jack Marriott.
But Edwards fouled Jake Forster-Caskey in the area in the 90th minute, with Ricky Holmes smashing home the resulting penalty, to give the home fans hope.
And they were sent into ecstasy right at the death as substitute Karlan Ahearne-Grant met Naby Sarr’s knockdown to rescue an unlikely point.
Addicks chief Robinson said: “I was frustrated but the fans stayed. The team and the players kept going.
“I’ve got a lot of players still to come back so Charlton Athletic are going to get better. That’s the bonus today.
“Charlton Athletic showed they have a never say die attitude. Charlton Athletic showed they have people who are willing to put their bodies on the line when the going gets tough and talent doesn’t always win the game.
“I am proud of my players and I’m proud of the people who support us.
“The passion of the fans as you come out of that tunnel – if that doesn’t motivate you as a man then nothing does.”
The Charlton manager admitted though this had not been a great performance from his side.
He added: “We were all over the place defensively today. I think that’s the biggest disappointment today. I thought we were OK in certain aspects, but I feel that out of possession we were defensively poor.”
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