The Catalan outfit led 2-0 at the interval courtesy of smart finishes from Neymar and Pedro.
Betis impressed in the second period, but Barca scored their third just past the hour mark when Fabregas converted from close range, before the Spaniard headed his fourth late on.
Betis were on the scoresheet late on with a penalty from Jorge Molina, but it was nothing more than a consolation.
Here, Sports Mole dissects the 90 minutes of action between the two Spanish rivals.
On target: 5
On target: 8
Was the result fair?
There is no question that Barcelona deserved to pick up all three points this evening, but the final score does slightly flatter the league champions. Had Betis taken one of their many opportunities in the first period, it might have been a different story. That said, the home side never looked capable of recovering after falling 2-0 behind late in the first half. It was another composed, strong performance from the Catalan giants.
Real Betis's performance
Basement side Betis were impressive for long spells this evening, but have ended up losing 4-1. The fact that they played so well and still lost by such a margin is perhaps a bigger worry for Pepe Mel than the defeat itself. Mel selected an attacking lineup in Seville, but once more his defence let him down. Barcelona were not made to work for any of their four goals this evening, with defensive mistakes apparent on each occasion.
Losing Lionel Messi to an early injury was hardly ideal, but his absence did not harm Barcelona's performance. In truth, they were not at their best for long periods, but had enough to score four times, which is a worry for the rest of the league. There is no doubt that their approach has changed this season, but it is perfect for these type of matches. The final score slightly flattered them, but one always felt that they could go up a few gears if needed. They enter the international break three points clear at the top of the division.
Sports Mole's man of the match
Marc Bartra: It had been questioned whether the centre-back had the credentials to emerge into a first-team player for Barcelona. Well, the Spaniard has made his point this season. It was another mature performance from Bartra in Seville as he showed his defensive instincts throughout the 90 minutes.
Biggest gaffe of the match
For 35 minutes, Betis more than matched the league leaders. However, their defence fell apart in the latter stages of the half. Twice Betis attempted to play offside in quick succession and they were punished on both occasions. It is not too difficult to see why and where they have struggled this season.
Overall, Jose Gonzalez had a fairly low-key evening in Seville. The Spaniard issued just the one yellow card in an end-to-end first period, while free kicks were few and far between as he let the match flow in the correct areas. The second period followed a similar pattern, with Gonzalez going about his business with minimum fuss.
Real Betis: Betis will attempt to return to winning ways - and indeed move off the bottom of the table - when they travel to Sevilla on November 24.
Barcelona: The Spanish champions also return to action after the international break when they host Granada in La Liga on November 23.