Spanish Grand Prix poleman Fabio Quartararo topped the post-race test by 0.418s with an unofficial Jerez lap record, while Jorge Lorenzo crashed twice during the session.
The first of three one-day post-race this season, Quartararo – who became the youngest ever MotoGP pole sitter last weekend – led for much of the day at Jerez, before re-establishing himself in top spot late on with an unofficial lap record of 1:36.379s.
Jerez race winner Marc Marquez was the early pacesetter with a 1:37.672s, but was deposed by Honda stablemate Cal Crutchlow at the end of the second hour of running, with the Briton going three tenths quicker.
With the third hour just beginning, Petronas SRT Yamaha's Franco Morbidelli leaped up to top spot with a 1:37.293s, as he and team-mate Quartararo focused on bike set-up on Monday.
Around 20 minutes later, Quartararo took over from his team-mate with a 1:37.101s, which stood as the benchmark for much of the day.
Marquez proved his nearest challenger for some time, when he put in a 1:37.260s on the bike fitted with the carbon fibre-wrapped chassis HRC test rider Stefan Bradl raced with.
With just under an hour remaining, Crutchlow returned to the head of the times with a 1:36.797s lap quicker than Quartararo's qualifying lap record.
Quartararo entered the final 30 minutes of the session by regaining top spot, the SRT rider setting a new unofficial lap record of 1:36.379s which when unopposed through to the chequered flag.
Crutchlow remained second after 78 laps on his LCR machine, while Morbidelli returned to third in the latter stages with a 1:37.093s to push KTM's Pol Espargaro back to fourth.
Maverick Vinales completed the top five on the factory Yamaha as he tested solutions to improve the M1's traction, and was 0.007s clear of Suzuki's Joan Mir, who fell at Turn 9 in the afternoon.
Marquez ended his day early and was seventh in the end, with Alex Rins ninth. The Suzuki rider tested a swingarm wing, but broke it after just a handful of laps after running into a gravel trap.
Lorenzo was ninth on the sister works Honda despite crashing twice during the session; once at Turn 6 earlier in the day, and again at the fast Turn 11 in the closing seconds of running.
Takaaki Nakagami rounded out the to 10 on his year-old LCR Honda, edging 0.002s ahead of top Ducati runner Andrea Dovizioso, who led stablemates Francesco Bagnaia [Pramac], Jack Miller [Pramac] and Danilo Petrucci.
Valentino Rossi completed 74 laps on his M1 on Monday, but was a low-key 17th and 1.677s off the pace in the end. He shadowed KTM's Johann Zarco and top Aprilia Aleix Espargaro.
Andrea Iannone, who missed the Jerez race after hurting his ankle in an FP4 crash, was cleared to run in the test. However, after experience too much pain when he attempted to complete some laps, he ultimately abandoned his programme.
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