I've now had a chance to watch the game, with the benefit of knowing the scoreline.
That last bit is relevant in that I can see how being a bag of nerves amplifies any insecurity on the ball, let alone instances we lose the ball. Lindelof and Case teaming up to send Williams through on goal was far worse, but we were 2-0 up by then so easily dismissed.
It really wasn't anywhere near as bad as made out to be, certainly nothing that trumps being involved all four times we hit the back of the net: ball recovery starting the Garnacho offside goal and Hojlund penalty, assist for Case and Bruno. Quite easily a contestant for MotM.
The clear and very specific issue is the link-up with Dorgu. Dorgu isn't a great passer and regularly passes to Ugarte. One ball gets trapped under his foot as he tries to cushion it. It was more a shot than a pass and he loses possession, in midfield, miles away from the goal albeit with Athletic executing the counter swiftly. There's also a diagonal clearance across the box that finds an Athletic player who immediately loses it. Can't see much else he could do with that hospital pass, Dorgu should have instead gone for a much simpler and less compromising pass to Yoro by the touchline. A few other times Bruno tries to pivot with Dorgu but he instead passes back to Ugarte, who loses the ball twice and the other times he doesn't it's usually a boring pass back to Yoro. I'm not blaming Dorgu there, the Athletic defenders always positioned themselves to block the pass back to Bruno, obviously. The relevant overriding issue is that circuit wasn't working at all: too static, predictable and easy to contain.
On that note, not sure why people are bitching about Garnacho. He was lively and probably the one concern keeping their backline pinned back early on when they could have otherwise ran us over given the way we started.