Arsenal had looked on course to record a 12th consecutive win in all competitions after a superb Granit Xhaka free-kick and a controversial Pierre-Emerick Aubameyang strike had cancelled out Luka Milivojevic's penalty on the stroke of half-time.
But the Palace captain, who missed from 12 yards in the defeat at Everton last weekend, made no mistake in securing a 2-2 draw when referee Martin Atkinson awarded the hosts a second penalty of the afternoon.
He said: "The two teams are sad I think. For us the first half was not easy. When they scored it is the moment when we are on the pitch with the control, but not doing a lot of things in the attacking third. In the second half we scored two goals in two actions. They were pushing with their supporters and every player was attacking us.
"In this moment we needed the control because we lost our position and we needed to have scored the third goal, we needed to be calm. We cannot do a good transition from this. I wanted to push, I wanted to continue to find our moment to win the match, but we could not.
"When you are defending a lot in your box, that can happen. Is it a penalty or not a penalty, it's not my work. I respect the referee's decision and we need to not concede chances and to have more control with the ball and keep the opposition outside our box. We could not do that today."