To me it doesn't matter much what you call it, luck, being clinical, being wasteful. To me there's an element of luck there as one team has little influence on the finishing of the other team. Gundogan could have taken a perfect penalty, not much Mourinho or our players could have done. Bergwijn could have skied his shot, without Guardiola or City doing anything different.
Regardless of what you call it I think those stats at least try to form an objective perspective to what we could all see (City creating way more and better chances). I find that quite interesting, though more so when the xG numbers differ more from my impression.
Either way, impression or stats, you can't rely on clinical finishing and the opponents missing chances to win. That's why I thought the Liverpool performance overall was better, even though we lost that one and won this one.