Didn't De Gea also save one in a FA cup semi final?
Doesn't matter when he saved them, fact is he only saved 3, I don't ever remember him bring criticised for it.
I really don't think penalty saving is worthy criticism. He's saved 11 out of 64 he's faced professionally. That's nearly a one in six record. Buffon has almost a 1 in 3 record, VDS record is similar to De Gea.
Penalties are as much mental as physical, you have about half a second from when the ball is struck until it hits the net. I remember seeing Peter Shilton talking about how he would wait until the ball was struck and then dive, he wasn't quick enough to react and it looked like he was diving after the ball hit the net. He was quite rubbish at saving penalties and the Italia 90 shootout is one he is negatively remembered for.