The penalty wasn't the biggest issue for me, the issue is Luiz will always find himself in these situations because he is an average defender. He went from being in front of the ball and man, to behind the ball and man unable to recover.
I've said before there are different levels of defenders: (consistently the key word)
1) can't defend their situation or others situation,
2) can only defend their situation,
3) can defend their situation and others situation.
The top defenders are the 3rd.
1) can't defend their situation or others situation,
2) can only defend their situation,
3) can defend their situation and others situation.
The top defenders are the 3rd.
Look at Holding in that situation, he has to adjust & cover the gap that Luiz has exposed, in turn Bellerin would then take his man. Neither of them acted accordingly to cover Luiz (who is the main culprit). See the difference between that and Gabriel here https://twitter.com/Dezildezzz/status/1356703698873942018?s=19
It's okay dealing with your own situation, but that does nothing for the team if you defend your own man but the team ends up conceding anyway.