Driving the Earl Bamber-backed Grove Motorsport team, Campbell made a better start from outside the front row to beat polesitter Dries Vantur at the first turn and never headed for the remainder of the hour-long encounter.
Turkey’s Ayhancan Güven also crashed out of Ventura at the first turn, before the Belgian ran past as he tried to fight back to drop a further two places to Italy’s Mirco Bartolotti and Germany’s Luca Stolz.
By the end of the first lap, Vanthoor had reclaimed fourth place from Stolz as Campbell edged out fellow Porsche 911 driver Guven by 1.8 seconds.
That margin was briefly reduced to less than a second before the Australian began to pull away as Guven fell into the clutches of Bartolotti and Vantour was closing in on the 15-minute mark.
Bartolotti then took second on the inside of turn six, with Guvin eventually ordering past Vantur, who ran off the track during a dogged defense of third.
The scuffle allowed Campbell to extend his advantage at the front to over 5s, while Vantour increased his pace to close in on Bartolotti.
#32 Belgium Audi R8 LMS GT3: Dries Vanthoor, GT Sprint Cup
The Lamborghini and Audi drivers remained side by side for the second half of the race, while Campbell’s lead fell to 1.6s at the checkered flag.
Ventura had to settle for third behind Bartolotti after a small mistake at the end.
Stolz eventually caught Guven, who had lost contact with the top three. After a fierce battle for several laps, the Mercedes driver capitalized on a mistake to get past and come home in solitary fourth.
Guven was the cork in the battle for fifth place in the closing stages, with Tristan Vauthier (France), Michael Benyahia (Morocco) and Daniel Juncadela (Spain) lining up behind.
Benyahia made a couple of late charges inside Vauthier, the second of which ended in contact and retirement after damaging his McLaren 720S, while Vauthier also lost ground.
Guven held off Bruno Baptista to take fifth at the finish, the Brazilian overtaking Hunkadela on the final lap, who was then demoted to ninth due to a 5-second off-track penalty.
That lifted Chinese Taipei’s Evan Chen to seventh, Vauthier to eighth, and Switzerland’s Yannick Mettler rounded out the top 10.