The Spaniard has often been criticised in the media this term – unfairly, perhaps – but has been lauded in all quarters since helping restrict Real to a single Cristiano Ronaldo goal on Wednesday night.
Given the boss never had any doubts about the youngster's quality and potential, recent tabloid speculation about a summer exit would appear to be wide of the mark, as more improvement is expected of the 22-year-old next season.
"That's the journalism," Sir Alex told MUTV. "It's fickle.
"I wouldn't worry about that [any over-the-top praise]. It didn't worry us before so why should we worry after it?
"The boy has shown that he has got terrific ability. He's got to adapt to the English game and we know there will still be some occasions where he is going to find it difficult in terms of the physical part of it. But he's getting stronger and, next year, he'll be better.
"He had a fantastic night as he made three exceptional saves. Their keeper, Diego Lopez, made two, too, so it was a night when both goalkeepers excelled on the big occasion."