Messi, meanwhile, is the top scorer in the Spanish top flight with 19 goals from 20 games.
Four more goals followed, starting with Messi's explosive finish and followed by Suarez's as he volleyed home Rakitic's pinpoint cross.
The match saw Messi reach two more personal milestones of his own, the Argentina star having assisted a goal in five LaLiga matches in a row for the first time in his career.
Barcelona coach Ernesto Valverde was delighted with victory over Real Betis on Sunday night.
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Barca, the only unbeaten side in Europe's top five leagues, lead the way in La Liga with 54 points after capitalising on second-placed Atletico Madrid's 1-1 draw with Girona on Saturday and third-placed Valencia's 2-1 defeat at Las Palmas.
The floodgates opened in the second half, with Bale adding his second from a towering header and Luka Modric expertly whipping home Real's fourth. However, once he had the bit between his teeth, he led Betis a merry dance, scoring twice and setting up a second for Suarez during a thrilling conclusion to the game.
"We played well and Messi was incredible", Valverde said in his postgame news conference. It was then that Messi took full advantage after defender Zouhair Feddal had surrendered possession and embarked upon a trademark mazy run into the penalty area, where he beat keeper Antonio Adan easily.
He was replaced by France worldwide Samuel Umtiti, who returned after a long injury layoff.
Barcelona: Marc-Andre ter Stegen 6, Nelson Cabral Semedo 6, Gerard Pique 6, Thomas Vermaelen 6, Jordi Alba 6, Sergi Roberto 7, Sergio Busquets 7, Ivan Rakitic 7, Andre Gomes 6, Lionel Messi 9, Luis Suarez 8. Yet he ended up with two goals and one assist.