Six-time MotoGP champion Marc Marquez had a very successful first day as a Ducati rider, placing in the top four in the sole post-season test day at Valencia.
The 30-year-old, who had spent the entirety of his premier-class career so far with Honda, looked to take to the 2023-spec Ducati Desmosedici being handed down to the Gresini team like a duck to water.
He was towards the top of the timing screens for the vast majority of the seven-hour test at Valencia's Circuit Ricardo Tormo and even had a brief spell leading, before ultimately being shuffled down the order somewhat.
Aprilia rider Maverick Vinales maintained his reputation - a reputation he personally loathes - as a testing specialist by going quickest with a 1m29.253s, just three tenths of a second off his own lap record from the preceding weekend.
He was nearly usurped, however, by a late glory run by KTM's Brad Binder - with Binder going 0.028s slower before crashing at Turn 5 on his next attempt.
Marco Bezzecchi, who had a huge disagreement with Marquez during the Valencia round at the weekend, ended up right ahead of Marquez - and four places ahead of his new team-mate Fabio Di Giannantonio, who had an assured debut with the VR46 team just a day after being confirmed for 2024.
Raul Fernandez was fifth-fastest and a frontrunner for much of the day. Fernandez ran with the Aprilia test team, as his 2023 employer RNF Aprilia is not being granted grid slots for the 2024 season.
It is expected that RNF will be replaced by NASCAR team Trackhouse on the grid - with Trackhouse set to retain both Fernandez and Miguel Oliveira, currently injured.
Marquez's brother and new Gresini team-mate Alex was sixth-fastest and felt the Ducati GP23 was a step forward relative to the GP22 he'd ridden all season.
A complicated new KTM aero arrangement made its debut on a camouflage-liveried RC16, ridden by both Jack Miller and Binder - and proving immediately competitive.
Also immediately competitive - somewhat startlingly so - was new Honda recruit Luca Marini, who like Di Giannantonio had only been confirmed for 2024 on Monday.
On a day on which both Honda team boss Alberto Puig and LCR Honda boss Lucio Cecchinello felt riders' feedback strongly suggested the RC213-V prototype brought to Valencia was a significant step forward, Marini placed 10th, just seven tenths off the pace.
Ducati's works team was led by Enea Bastianini in eighth, with reigning champion Pecco Bagnaia in 11th.
Bagnaia's main 2023 title rival Jorge Martin was 15th for Pramac Ducati, having twice crashed his GP24 prototype in quick succession relatively early on,
Yamaha, which trialled new aero and claimed positive impressions from both that and an incremental update to the prototype 2024 engine, was headed by Fabio Quartararo in 12th, Quartararo having seemingly recovered from the fever that compromised his Valencian Grand Prix.
There were quietly decent debuts in new surroundings for the likes of Franco Morbidelli (Pramac Ducati), Johann Zarco (LCR Honda), rookie Pedro Acosta (Tech3 Gas Gas, pictured above) and Alex Rins (Yamaha) - though Zarco and Rins did have crashes.
Aprilia test rider Lorenzo Savadori gave a public runout to the manufacturer's new carbon-fibre chassis - while regular rider Aleix Espargaro had to cut his day short after just a handful of laps, owing to a "worsening" of the fibula fracture that he's been nursing since Qatar earlier this month and all through the Valencia weekend.
1. Maverick Vinales (Aprilia), 1m29.253s
2. Brad Binder (KTM), 1m29.281s
3. Marco Bezzecchi (VR46 Ducati), 1m29.346s
4. Marc Marquez (Gresini Ducati), 1m29.424s
5. Raul Fernandez (Aprilia), 1m29.516s
6. Alex Marquez (Gresini Ducati), 1m29.638s
7. Fabio Di Giannantonio (VR46 Ducati), 1m29.662s
8. Enea Bastianini (Ducati), 1m29.796s
9. Jack Miller (KTM), 1m29.910s
10. Luca Marini (Honda), 1m29.956s
11. Pecco Bagnaia (Ducati), 1m29.970s
12. Joan Mir (Honda), 1m30.051s