Ducati has not been dethroned throughout the five days of official testing this winter, with its riders taking top honours in Malaysia and Portugal.
Bagnaia was first out on track on Sunday on his factory team Ducati and would end the day 0.296s clear of the field with a new unofficial lap record of 1m37.968s.
Though the world champion was first on track on Sunday morning, the opening hour was topped by Pramac counterpart Jorge Martin. The Spaniard would crash just moments into hour two, however, but suffered no ill-effects from the tumble and re-established himself at the top of the pile with a 1m38.717s.
Come the end of hour three, Bagnaia took charge with a 1m38.154s which would stand as the benchmark until the final 50 minutes of the session, when he fired in a 1m37.968s on fresh soft rubber.
With most wrapping up well before the chequered flag, Bagnaia went unchallenged through to the chequered flag to begin the first steps of his title defence in fine form on a bike (alongside the Aprilia) he believes is “unbeatable” at the moment.
Pramac’s Johann Zarco made a late play for second with a 1m38.264s on his GP23, but was still 0.296s away from his stablemate.
Shadowing Zarco by 0.038s came fellow Frenchman Fabio Quartararo, who rounded out the top three to give his Yamaha team some hope to cling onto as the new season dawns.
Having felt after Saturday’s session that Yamaha “will not be ready” for the first round of 2023 as he struggled massively on the M1, the Japanese marque made a breakthrough on Sunday by reverting to 2022 settings.
Fabio Quartararo, Yamaha Factory Racing
Photo by: Gold and Goose / Motorsport Images
This allowed Quartararo to produce a 1m38.302s, a lap some 1.3s quicker than he managed on Saturday, to end up third overall.
Yamaha also debuted its Formula 1-style rear wing on Sunday, though Quartararo told the media that the massive appendage didn’t seem to make much difference and was unlikely to be raced right now.
Alex Marquez had two crashes on Sunday but was still seventh-fastest on his Gresini Ducati ahead of Martin, KTM’s Brad Binder and Aprilia’s Aleix Espargaro – who admitted he may have to undergo surgery this week due to a fibrosis issue in his arm.
Gresini sophomore Fabio Di Giannantonio was unable to ride on Sunday due to a concussion he suffered in a crash on Saturday, with the Gresini rider blaming Algarve’s ‘wall-like’ gravel for his injury.
The 2023 MotoGP season begins on 24-26 March with the Portuguese GP, and will mark the first time in history that a sprint race will feature on the weekend schedule.