You can't be serious right now! Lol, wow. Barbatos had one barely functioning arm, extreme structural damage and Mika was controlling the thing with his mind, she was fighting a unconscious person. It just so happens she decided to enter the fray when Barbatos was essentially out of gas and likely sustained too much structural strain to handle all it's "break-neck" actions. Just reason for a moment that she got shitted on when Mika was serious and Barbatos wasn't smashed up in their previous encounter...what changed in this encounter? Everything was in her favor.
It still does not changed the fact that she survived such a long battle between her and Barbatos on their last skirmish there which no one without AV seems to had been able to do since we enter S2. On the last battle of course it does not really count as Julietta entering a totally different fray of battle condition however, i think you are still selling her short there.