De Gea was selected ahead of Anders Lindegaard for the crunch clash against the club's rivals at Anfield but appeared to be troubled by crosses throughout.
His poor judgement then led to Daniel Agger giving the hosts the lead after the Dane nodded a corner, which De Gea had attempted to collect, goal-ward.
Finally, Dirk Kuyt's late goal had the young shot-stopper beaten easily and clinched a fifth round berth for Kenny Dalglish's men at the expense of the Red Devils.
However, despite De Gea's nervy performance, Owen insisted that the former Atletico Madrid man will come good for United.
"One comment on yesterdays game. Don't agree with all this negativity towards De Gea," the forward wrote on his Twitter.
"Admittedly he has made a couple of mistakes this season but listening to some people you would think he had a nightmare yesterday.
"I'm not having either goal was his fault. The problem is, once you get labelled, mud sticks and now any tiny mistake is magnified. Other keepers make similar mistakes and nothing gets said.
"The ball was on the six yard box for the first goal. He has to go for it. He also needs to watch the flight of the ball. There is then six players in front of him. There is nothing he could do. The free header was the problem, not the keeper.
"He couldn't do much with the second goal either. Is the problem not just a case of us not winning the first ball and not picking up a runner?
"In my opinion two bad goals to give away but to blame everything on the keeper is totally wrong. The lad will be a top keeper, he is only young. Harsh to blame him for everything."
Owen also hailed the club's fans for backing the young shot stopper, adding: "Must say, as you will be quick to remind me, I've watched a lot of home games this season! The support from behind both goals for him has been brilliant.
"The fans know he needs their support, his confidence needs boosting. I'm sure he will repay that support for years to come."
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