A bright start from Elche had a much-changed Barça on the back foot, though it was Lamine Yamal who came closest to opening the scoring with his first touch after five minutes, shooting over the bar when well placed.
The visitors uncharacteristically lost possession on a few occasions before Raphinha won and converted a 14th-minute penalty to settle the nerves.
Undeterred after going behind, Elche weren’t overawed and continued to look for openings, with David Affengruber just unable to steer his diving header from a well-placed corner goalwards.
Lamine began causing all sorts of problems down the hosts’ left-hand side, whilst Karim Adeyemi was just a little off the pace on the opposite side, and yet the visitors were indebted to Eric Garcia as the half continued, with his last-ditch clearance saving a certain equaliser.
Elche cut open the Barça defence again as half-time approached, and despite being unmarked by the penalty spot, Ali Houary just couldn’t make a proper connection with the goal gaping.
That miss would prove costly and the hosts were made to pay during first-half stoppage time as a wayward ball found its way to Raphinha to play in Karim Adeyemi, who made no mistake as he slotted a right-footed effort past Matías Dituro for his first goal for the club.
As might be expected, the visitors didn’t need to exert themselves too much as the second half got underway, but this did invite Elche onto them on several occasions before the hour mark, with the closest the hosts came to scoring being when Tete Morente’s shot on the turn hit the outside of Joan Garcia’s right-hand post.
The Barca custodian was then on hand to gather Morente’s cross, with Fer Niño ready to pounce. As Lamine and Adeyemi began to tire, they were replaced by Dani Olmo and Anthony Gordon, and the two combined to play in Raphinha to sweep home his second with just over 20 minutes to play.
Gordon was once again the provider four minutes later, streaking away from the home defence and drawing the goalkeeper to him before slipping in Fermín Lopez to score into an empty net.
Fermin’s brilliant turn on the edge of the box bought him some space to finish past Dituro with a fine left-foot shot, and Barça had five, with 12 minutes still to play.
The loss was Elche’s first at home in eight games (W4, D3), and meant that Martín Anselmi couldn’t join the five previous club managers (out of 24) to win their first fixture against Barcelona.
Hansi Flick’s side still haven’t drawn any of their last 36 LaLiga games (W30, L6), after this win.