Paco Alcacer ended his wait for a competitive goal in Barcelona colours as the holders ran out 7-0 winners over Hercules in the Copa del Rey, with Arda Turan hitting a hat-trick.

The Spain international forward endured 10 scoreless appearances on the back of his August switch from Valencia, but got in on the act as Luis Enrique's men ensured there was no repeat of their first-leg scare to book a place in the last 16.

The holders fell behind in a 1-1 draw with their third-tier opponents in last month's initial match and Luis Enrique plumped for a more experienced line-up this time around, boasting all six of his major signings for this season.

One of those, Lucas Digne, settled a slightly edgy Camp Nou eight minutes before half-time and Ivan Rakitic doubled the lead at the interval with a penalty.

Any doubts that the game was over as a contest were extinguished as Rafinha and Arda struck inside the opening 10 minutes of the second period.

But the biggest cheer of the night was reserved for Alcacer, who headed home amid suspicions of offside to go into the mid-season break with a considerable weight off his shoulders, while a late salvo ensured Arda departed with the matchball.

Rakitic, starting in midfield after being an unused substitute for Barcelona's previous two LaLiga matches, floated a pass into the path of Digne for the full-back to fire over in the fourth minute.

Hercules centre-back Rojas prevented Denis Suarez from converting Turan's low right-wing cross with a brilliant challenge in his own goalmouth, while Javier Mascherano was forced into last-ditch action at the other end as Chechu Flores pursued an unthinkable opener for the visitors.

A superb solo run worthy of the absent Lionel Messi from Suarez concluded with the former Villarreal man lashing into the side netting and, although his wait for a maiden Barca senior goal went on, another close-season recruit opened his account in the 37th minute

The Hercules left, where Suarez had his earlier joy, was the source of the goal, with Arda sending a low ball in for Rafinha's shot to be blocked, but the on-rushing Digne was able to prod the loose ball high into the net.

It was 2-0 before half-time as a wonderful lofted pass from goalkeeper Jasper Cillessen sent Rafinha storming towards the Hercules area. The Brazilian slotted in Arda, who was clumsily brought down by Fernando Roman and Rakitic steered his spot-kick under Ivan Buigues' dive.

Hercules' earlier resistance predictably subsided early in the second half as Rafinha lashed a rasping drive into the bottom left corner and further punishment was quick to arrive.

Arda was on hand with an emphatic diving header to dispatch Aleix Vidal's 55th-minute centre, further locking Camp Nou's focus on the need of another man to join the goalrush.

In the 73rd minute Alcacer responded, getting on the end of Rafinha's deflected cross for a simple headed finish.

With the relief still palpable that he ended that 576-minute wait for a Barcelona goal, Alcacer almost had a second three minutes later when his shot was blocked on the end of another fine Suarez run.

Arda's second came on the rebound as Buigues denied a seemingly buoyant Alcacer and the Turkey international concluded the rout in style by winning possession and curling home from the left-hand corner of the area.