Ansu Fati's superb second-half strike settled matters for Barca, who clinched a triumph that took them second in Group E amid intense speculation the club is set to appoint club legend Xavi as Ronald Koeman's successor.
Barca visits Celta this weekend, with Sergi unsure whether he will be overseeing that game or back leading Barca's B team in their home game with Sevilla's B outfit at Estadi Johan Cruyff.
"I told them [the players] how important the game was for the club before the game," Sergi said. "There are many players from the cantera that understood.
"I went all out with that, and I don't know whether or not it worked. But at least we won.
"On a personal level, the fact I am here representing the club that has given me everything is amazing. The players know where they are. Every day you fail to win you enter into a dynamic where you are wondering what you can do.
"It is a matter of work, and now that the dynamic is changing we have to take advantage of it. We have to look at what we have done well and do it better.
"I lived the game as if it were my team. The only way for us all to go together is for me to show serenity in order to convince them and help them improve.
"I cannot think about whether I will be there tomorrow. I want to help the club and I want to do what I am doing. There is not the slightest doubt [in that].
"Today we have won. Let's enjoy ourselves a little bit. God will decide if I will finish the week in Vigo or at the Johan Cruyff."