Barcelona didn't have an easy job at all though. It was like they were waiting for Valencia to score to start performing better. 
Lewandowski was on his very good day that he scored two goals. It is good to see him being beneficial for his team. Because he is one of top earners in the squad now. Therefore the expectations are bigger as well.
I still believe it could be his last year at Barcelona on one hand. He is 35 and has 2 years left on his contract. If he plays much extra this season then maybe the team could consider keeping him for one last year.
Lewandowski was on his very good day that he scored two goals. It is good to see him being beneficial for his team. Because he is one of top earners in the squad now. Therefore the expectations are bigger as well.I still believe it could be his last year at Barcelona on one hand. He is 35 and has 2 years left on his contract. If he plays much extra this season then maybe the team could consider keeping him for one last year.
At 35 years old I personally don't believe any big European team is interested in signing him, maybe if there is still a team interested in signing Lewandowski then it will be a team playing in the Saudi Pro League. But, because his contract at Barcelona expires in 2026 then I think it's not about Barcelona keeping him, but because Lewandowski is still under contract then Lewandowski will end his contract until 2026.
About the 1-2 win against Valencia, ofcourse, it is still a good result to at least get three points in the first match of the season. Although Valencia managed to score first it was also not a problem because afterall, the most important thing is the end result which will certainly remain good when it ends with three points. For the next La Liga match Barcelona will play at home, but I think it's still not easy because the next opponent is Bilbao.