In the tenth minute of Barcelona's opening day, action-packed 4-2 victory over Real Sociedad on Sunday night, there was a heartfelt minute of applause and singing for the recently resigned Lionel Messi.It was the first time in 17 years that the club did not have its best player ever among its ranks, and the mood towards the new era was subdued to say the least.But after 90 minutes of action, it is safe to say that the mood has changed. Yes, in the tenth minute of the second half, another round of 'Messi! Messi! 'songs…