Oh, I'm sure he'll learn from it - he looked gutted after that goal, and it's never a nice moment to feel like you let down your teammates.
But it's usually the case that a youngster (or really, just someone inexperienced) failing at something isn't the fault of that person alone. It's also the fault of the person who put them in that situation despite knowing the possibility of failure. In this case, that's Vicario, as someone who has ten more years of experience than Gray (or thereabouts).
And, if they do fail - it's usually not great leadership to yell at them for it when you had a hand in creating that situation. At least, that's how I try to lead, and what I understand to be good leadership.