Chris Coleman admits Lee Camp will be 'disappointed' after Reading were gifted the lead at the Madejski Stadium.
Sunderland were well in the game when Camp's weak clearance led to Reading regaining possession and putting the Cats defence under pressure.
In the same passage of play, Camp then spilled a tame effort from Sone Aluko and was slow to react to the loose ball, bringing down Jon Dadi Bodvarsson for a penalty, which was confidently dispatched by Liam Kelly.
Sunderland fought back well thanks to a stunning strike from Paddy McNair and a Lee Cattermole header but Sunderland's defensive fragility was again exposed.
A cross from Chris Gunter on the right wing wasn't stopped and sub Yann Kermorgant rose above Donald Love to head into the corner of the net, with Camp nowhere near it.
Sunderland were forced to settle for a point, doing little for the club's survival hopes.
When asked about Camp's mistake for Reading's opener, Coleman said: "Yes, Campy will be disappointed with that, it bounced off him, I could see he was disappointed.
"The penalty, is a good finish.
"But we came back from that and showed some spirit. I thought we would score again if I'm honest, it went quite here, Reading had a dip.
"That is the difference, in that bottom three, when the points are there with 20 minutes to go.
"You want it to go for you, you are wishing away all the negatives. If you are in mid table or top 10, your thinking is different, more positive.
"At the moment we look fragile, for all our effort and endeavour.
"Those one or two moments in one or two games when you are asked a serious question, one goal in it, we look like we can concede and it happened."
Sunderland on the brink and relying on others as Chris Coleman reacts to more dropped points
Sunderland should have had a penalty of their own half an hour in, Callum McManaman fouled by Dave Edwards but referee Steve Martin waved away the strong appeals.
Coleman added: "Yes, we thought it should have been a penalty.We were disappointed with that.
"If you look at where our bodies are in the box, if Macca escapes the challenge, it is a simple pass and a goal.
"Did it hamper what he was trying to do? It did, we thought it was a penalty."
Sunderland have been beset with injury problems all season, the squad lacking robust players, and they lost Bryan Oviedo two minutes into the restart, the left-back replaced by Jake Clarke-Salter after McNair's equaliser.
Coleman added: "It was his hamstring. He got to half-time, when he tried to go back out it stiffened up.
"He hasn't torn it but wasn't able to open up and run and sprint, obviously he had to come off."