I've been waiting for someone to say this - i did think about it a little, but let's be honest the danger came from the other flank with Mitoma and Estupinian
If you want to know if Tierney did ok or not, i noted Mitoma was on the right for Brighton earlier on in the first half, perhaps De Zerbi thought Tierney would be a weakness...
...clearly not, as Mitoma swapped flanks and on that side in the second half he trashed us
tbh Brighton probably would have gone ahead earlier if it had been Mitoma v Zinchenko