That may be the breakthough for him.
There is no doubting his talent, but he has completely failed to be worth consideration as a first team player this season & could have no complaints about not playing. Pep clearly spotted something in the run up to this game though & gave him his chance.
Even allowing for all the talk about how it 'wasn't working' with him on the left, he still put a cross in which was better than the one Liverpool scored from. On the right, he was just as dangerous as Bernardo Silva usually is, which is a huge compliment.
Now he needs to do it regularly. He could get 20 goals & 20 assists in this team if he got his act together.