Barcelona increased their lead at the top of the Primera Division table to three points by overcoming Real Betis thanks to goals by Neymar, Pedro and a Cesc Fabregas double.
But it was not all good news for the Catalans, who lost Lionel Messi to a hamstring injury midway through the first half.
It is the third time the four-time World Player of the Year has hurt his hamstring this season, and Barcelona have confirmed he will receive tests on Monday to determine how long he will be out for.
Despite the severity of the scoreline, this was not an easy night for Gerardo Martino's side, who were under pressure from their hosts in the first half, until Neymar broke the deadlock on 35 minutes.
Less than two minutes seconds later, Pedro doubled the lead to put Barca's minds at ease, and Fabregas rounded off the victory in the second half by netting a brace.
Jorge Molina scored a penalty in injury-time but it was scant consolation for Pepe Mel's side, who stay bottom of the league.
Martino fielded an experimental side, starting with Marc Bartra and Martin Montoya in defence over Javier Mascherano and Adriano, while Alex Song was chosen ahead of Sergio Busquets - who had been carrying a knock after the win over AC Milan on Wednesday. Andres Iniesta and Alexis Sanchez were left on the bench.
Barca's task was complicated by a torrid pitch which impeded their slick passing game and things got worse when Messi limped off midway through the first half.
Moments before the forward appeared to injure his ankle following a challenge with Betis defender Caro, but his club announced via its official Twitter account that it is a hamstring injury.
Barca were grateful to Victor Valdes for keeping out two attempts in quick succession with less than 20 minutes played. First the goalkeeper thwarted Jorge Molina from close range and then dived across his goal to save a near-post header from Juan Carlos.
The more Betis attacked the more they left themselves open and they were caught out with 10 minutes remaining in the first half.
Song played in a perfect through ball for Fabregas on the right hand side and the former Arsenal player played across to Neymar, who side-footed home.
Almost immediately after Betis had re-started the game, Pedro broke down the left wing and raced towards goal, curling the ball into the right hand corner with a fine finish.
The Spain international has played second fiddle to Alexis in recent weeks, but notched his sixth goal of the season.
Pedro was close to getting another goal on the stroke of half-time when Neymar set him up, but Jordi Figueras was able to lunge in and put him off, the ball going wide for a goal kick.
Joan Verdu nearly got one back for Betis a minute into the second half, volleying inches wide of the post and then Markus Steinhofer hit the post from the edge of the area.
Barca soon reasserted their authority, and it took a double save from Guillermo Sara from Neymar to prevent a third.
It was left to Fabregas to put the game out of sight.
On 63 minutes he nudged the ball into the net after receiving a cut-back from Montoya, and with 11 minutes left the midfielder scored his second, ghosting in ahead of defenders to nod in a looping cross from Dani Alves.
Alves gave away a penalty in stoppage time for dragging down Javier Matilla, and Molina converted with virtually the last kick of the game.
Barca have won 12 of their 13 league games and for the first time this season have some breathing space at the top, but things are far less rosy for Betis, and Mel's time in the dugout could be running out.