As I've said before, De Gea saves Utd far more points than he costs us with some astonishing saves.
Utd's loss was more down to not having a lethal striker, or any striker, than it was to De Gea.
Middlesbrough have Zach Steffen on loan from Man City. There’s been at least 3 times this season he‘s passed the ball directly to to an opposition player who has scored. Boro have been knocking goals in for fun, Utd haven’t. Utd’s biggest issue is a striker. Look at your best goal scorer and then imagine what points difference Harry Kane would have made. And imagine one decent central defender… champions, or at least challenging for it.