The Spaniard’s dominance shows no signs of abating after he clinched his second victory of the day – and third of the weekend – to remain unbeaten after the first three rounds of the championship.
Once again he led from start to finish in front of his home fans as he won by nearly seven seconds, with the win also marking Ducati's 350th race victory in the series.
Highlights: Rea wins Barcelona Superpole after elbow bump with rival Toprak
Reigning champion Jonathan Rea battled Bautista's team-mate Chaz Davies, his own Kawasaki team-mate Leon Haslam and Pata Yamaha rider Alex Lowes throughout the race, eventually picking up his ninth second place of the season.
Davies completed the podium after making a mistake on the final lap to let four-time champions Rea through.
Bautista led from the start, despite Michael Ruben Rinaldi (BARNI Racing Team) and Michael van der Mark (Pata Yamaha WorldSBK Team) colliding in a big crash.
Big crash as Rinaldi and Van der Mark collide at start
Bautista went clear at the front of the Superpole Race, just as he did in Race 1 on Saturday, leaving the rest to battle it out for second.
Alex Lowes and four-time champion Jonathan Rea fought it out in the closing laps with the Northern Irishman eventually taking the spoils.
However, Rea, was 5.7seconds behind the winner in a ominous sign of the Spaniard's dominance.
1. Alvaro Bautista (ARUBA.IT Racing – Ducati)
2. Jonathan Rea (Kawasaki Racing Team WorldSBK)
3. Alex Lowes (Pata Yamaha WorldSBK Team)
4. Chaz Davies (ARUBA.IT Racing – Ducati)
5. Tom Sykes (BMW Motorrad WorldSBK Team)
6. Eugene Laverty (Team Goeleven)
Razgatlioglu sets fastest free practice time at Acerbis Catalunya
World Superbike 2020: Is Jonathan Rea going to triumph again?