From the middle of the second row, Bautista immediately rocketed into a lead he would never relinquish for the duration of the 20-lap contest, eventually beating nearest rival Jonathan Rea by 8.6 seconds.
The Spaniard now enjoys an enhanced 44-point lead at the head of the standings ahead of Toprak Razgatlioglu, who could only manage fifth.
It was reigning champion Razgatlioglu who provided Bautista's closest opposition for most of the race, as a rapid getaway for the Yamaha rider propelled him from eighth on the grid into an early second place.
Front-row starter Alex Lowes settled into third as his Kawasaki teammate Rea slipped to seventh, behind the second Ducati of Michael Ruben Rinaldi, poleman Iker Lecuona and Axel Bassani.
Rea gained a place at the start of the third lap as Rinaldi ran wide at Turn 1, dropping himself down the order, but spent numerous laps holed up behind the satellite Motocorsa Racing Ducati of Bassani.
It took until the ninth lap for Rea to finally make his way by Bassani for fifth place, by which time Lowes had slipped behind the Honda of Lecuona in the fight for third.
With the two Kawasaki riders now lying astern, Rea eased his way by Lowes for fourth on lap 14 and passed Lecuona for third next time by.
By this stage second-placed Razgatlioglu was struggling for pace, having allowed Bautista to escape at the head of the field to the tune of five seconds, and was quickly reeled in by Rea.
The inevitable pass for second came on lap 17, and Razgatlioglu then found himself coming under pressure from surprise package Garrett Gerloff, who had cleared Lowes and Lecuona with a double overtake at Turn 1.
Next time by, GRT Yamaha rider Gerloff passed Razgatlioglu and held on for third place to score his first podium finish since last year's Donington Park round.
Razgatlioglu would lose one more place in the closing laps to a resurgent Rinaldi, who came back from ninth after his early mistake to finish fourth.
Polesitter Lecuona had to be content with sixth place ahead of Lowes, while Bassani eventually made it home eighth.
Completing the top 10 were Andrea Locatelli (Yamaha), whose race never recovered from running wide at Turn 1 on the opening lap, and Eugene Laverty, who was best of the BMW runners in 10th to match his best finish of the season so far.
Xavi Vierge was a disappointing 12th on the second Honda behind the second Bonovo BMW of Loris Baz.
Neither of the works BMW riders finished, with Scott Redding crashing out at Turn 1 on the third lap and Michael van der Mark succumbing to technical issues.
Barcelona WSBK - Race 1 results:
| Cla | # | Rider | Bike | Time |
|---|---|---|---|---|
| 1 | 19 |  Alvaro Bautista |
Ducati | - |
| 2 | 65 |  Jonathan Rea |
Kawasaki | 8.665 |
| 3 | 31 |  Garrett Gerloff |
Yamaha | 9.289 |
| 4 | 21 |  Michael Ruben Rinaldi |
Ducati | 10.783 |
| 5 | 1 |  Toprak Razgatlioglu |
Yamaha | 13.568 |
| 6 | 7 | Iker Lecuona |
Honda | 13.655 |
| 7 | 22 | Alex Lowes |
Kawasaki | 14.013 |
| 8 | 47 | Axel Bassani |
Ducati | 14.839 |
| 9 | 55 | Andrea Locatelli |
Yamaha | 29.775 |
| 10 | 50 |  Eugene Laverty |
BMW | 30.094 |
| 11 | 76 |  Loris Baz |
BMW | 30.390 |
| 12 | 97 | Xavi Vierge |
Honda | 31.755 |
| 13 | 2 | Roberto Tamburini |
Yamaha | 33.055 |
| 14 | 44 | Lucas Mahias |
Kawasaki | 35.962 |
| 15 | 23 | Christophe Ponsson |
Yamaha | 37.498 |
| 16 | 3 |  Kohta Nozane |
Yamaha | 45.108 |
| 17 | 99 | Oscar Gutierrez | Kawasaki | 46.958 |
| 18 | 36 |  Leandro Mercado |
Honda | 55.315 |
| 19 | 52 |  Oliver Konig |
Kawasaki | 57.534 |
| 60 |  Michael van der Mark |
BMW | ||
| 45 | Scott Redding |
BMW | ||
| 29 |  Luca Bernardi |
Ducati | ||
| 5 |  Philipp Oettli |
Ducati | ||
| View full results | ||||
