Diogo Jota’s emphatic 13th-minute finish put the Reds ahead in front of around 40,000 fans, but Alejandro Berenguer equalised for the visitors eight minutes into the second half.
An apparent ankle injury forced Andy Robertson off shortly before the break, but an otherwise positive afternoon saw Virgil van Dijk start and play around 70 minutes.
The opening stages were played out amid a party-like atmosphere as the Kop joyfully ran through its songbook.
There was a pleasing rhythm to Liverpool’s early work on the pitch too - and they got the goal Anfield craved with 13 minutes on the clock.