Barcelona have now played twice at Camp Nou this season and both games have seen 5-2 wins for the Catalan club.
Kevin Gameiro got one back for Valencia, but Gerard Pique made it 3-1 shortly into the second half and Luis Suarez came off the bench to add two more, before Maxi Gomez netted a consolation in added time.
The emphatic victory saw Barca return to winning ways following the 2-2 draw at Osasuna prior to the international break and the Catalans are now just two points off the top of the table as leaders Atletico lost at Real Sociedad.
For Valencia, meanwhile, it was a difficult start to life without coach Marcelino Garcia Toral, who was sacked on Wednesday. Here, a look at the major talking points from the game...
Ansu Fati is the future, not Neymar
Ansu Fati was picked as a starter for the first time as a Barcelona player and the 16-year-old made a lightning start to the game at Camp Nou, scoring a fine goal inside two minutes from a De Jong cross and assisting the Dutch midfielder with a brilliant run and pass which left the ball on a plate for his team-mate after seven minutes.
"He is an exciting player," De Jong said afterwards. "He has a great future." Coach Ernesto Valverde also praised the youngster. "He is a player with something special," he said. "He s mature for his age. What you see in training is what you see here. What he did today was impressive: he scored, he gave an assist and he nearly hit another one into the top corner."
While Neymar was booed by his own fans as he helped Paris Saint-Germain to a 1-0 win over Strasbourg in Ligue 1, Ansu Fati was given a standing ovation by Barca's supporters at Camp Nou. If the youngster can continue in this form, it will be he - and not the Brazilian - who is the future for the Catalan club.
Suarez will shine with more rest this season
Back from a calf injury he had sustained on the opening day in the 1-0 defeat to Athletic Club at San Mames, Luis Suarez came off the bench to rifle home a long-range effort within a couple of minutes of replacing Ansu Fati and later in the game, the Uruguayan produced another fierce finish from an Antoine Griezmann pass to make it 5-1.
Suarez has had his critics in recent seasons and his record in Europe in particular is poor, but with greater rest and possibly used as an impact substitute as he was in this match, he can still make an important contribution to Barcelona's attack. In addition, his two goals mean he is now joint-third top scorer for Barca in the history of La Liga, level with Laszlo Kubala on 131 league strikes for the Catalan club. Not bad.
"He is the best striker in the world," midfielder Sergio Busquets said afterwards. "He gives us so much in terms of work-rate, hunger and goals. We are pleased to have him back again." With Griezmann struggling in a central role, the return of Suarez is definitely good news.
Arthur, Busquets and De Jong is Barcelona's best midfield trio
Valverde has experimented in midfield so far this season, starting a number of different players in the centre of the park, but the general view among fans is that Barca's best trio is Sergio Busquets, Frenkie de Jong and Arthur. And against Valencia, Valverde obliged. All three started - and they did not disappoint.
With Busquets in a deeper role, De Jong has greater freedom to attack and that showed as the Dutch midfielder set up Ansu Fati's goal early in the game and then scored himself after seven minutes. It was his best performance yet for the Catalan club and he will continue to improve. "We know he can get forward in that position," Valverde said. "He can still be more decisive at times."
While Busquets pulled the strings from deep and De Jong stole the limelight with his goal and assist, plus a 100% passing record, Arthur was perhaps the pick of the three. He brings more control to the midfield and that can help Valverde's side to improve their overall play. Thwe Brazilian did that as a substitute against Osasuna and impressed again versus Valencia. Even if they are unlikely to start together against Borussia Dortmund on Tuesday, this triumvirate looks like the way forward.
Barca's defence is still too leaky
Barcelona's 12 goals in La Liga this season make them the top scorers after four games, but only two teams in the division have conceded more than the Catalan club so far: Betis and Villarreal. Those two have let in eight apiece, while Barca have conceded seven, and the Catalans' back line was shaky again in the win over Valencia.
Gerard Pique and Clement Lenglet are not the quickest and Barcelona definitely miss a fully fit Samuel Umtiti, a beast in his first season at Camp Nou before injuries took their toll and restricted his influence and involvement. Meanwhile, Jordi Alba is caught out at times when he attacks and Nelson Semedo is an upgrade on Sergi Roberto, but still needs to improve at right-back.
The second goal was somewhat irrelevant as it came in added time with Barca 5-1 up, but Marc-Andre ter Stegen had to make a couple of important interventions earlier on and better teams than Valencia may exploit the spaces left by Barca and their lack of speed at the back.
Valencia will take time to recover from Marcelino's sacking
The last time Barcelona played Valencia, the Catalans were on the receiving end of a painful 2-1 defeat in the final of the Copa del Rey. In fact, the league champions could not beat Valencia in any of the teams' three meetings last season (with two draws in La Liga).
But after Marcelino's surprise sacking on Wednesday night, a repeat of that never looked likely. Valencia are a club n chaos now and new coach Albert Celades will have his work cut out at Mestalla. "Footballers are people and it's normal they are affected," he said after the game. The players had not wanted Marcelino to leave.
"Valencia's Twitter account sent out a message of "unity" after the game, to which hundreds of furious fans responded with angry messages aimed at owner Peter Lim for his treatment of Marcelino. Celades, meanwhile, will get on with things. "Little by little, I hope our work is reflected on the pitch," he said. With the mood as it is, that may take some time.