The opening day of the Formula 1 post-season test in Abu Dhabi has ended with Formula E champion Nyck de Vries fastest for Mercedes.

De Vries recorded a 1:23.914s in the closing 30 minutes of the day to leave him fastest over Kiwi youngster Liam Lawson at the wheel of an AlphaTauri.

It was a strange day from Mercedes, which remained silent on social media despite its chart-topping pace and the presence of George Russell.

Its last communication remains confirmation of its intent to appeal the outcome of the Abu Dhabi Grand Prix.

Australian Oscar Piastri, gaining his first taste of contemporary F1 machinery, was third fastest for Alpine, 0.006s away from Lawson but more than a second down on the best time of the day.

A mix of cars and drivers were on track in Yas Marina as young drivers aboard the current-spec machinery shared the circuit with race drivers aboard modified ‘mule’ cars performing 2022 tyre testing.

That saw the likes of IndyCar winner Pato O’Ward on track for McLaren alongside Valtteri Bottas, who spent his first day with Alfa Romeo Sauber.

O’Ward waxed lyrically of the opportunity at the end of the day’s running, having logged almost two grand prix distances.

The Mexican was piloting a standard McLaren MCL35M, as was raced last weekend, while Daniel Ricciardo ran a modified version to simulate the expected grip levels from the 2022 cars.

Most teams’ mule cars are older spec machinery.

At McLaren, the change from Renault to Mercedes power ahead of 2021 mean its only option was to tweak one of its latest machines to suit.

Aston Martin had a similar approach, with two AMR21s in action for Lance Stroll and Nick Yelloly.

That offered a direct comparison with regards to 2022 lap times over those currently seen and suggested the performance drop for next year will not be as significant as initially predicted.

Ricciardo, who was the fastest ‘mule’ runner, logged a time of 1:27.508s in the morning session at a time when O’Ward topped the timesheets with a 1:25.260s in what was his first taste of a Formula 1 car.

By comparison, Ricciardo’s time during Free Practice 3 for last weekend’s Abu Dhabi Grand Prix – the most comparable session to today’s running – saw the Australian log a 1:24.733s.

At the end of the day, the Italian GP winner had improved to 1:26.252s, a difference of just 1.5s.

Stroll’s best was a 1:26.579s, approximately 1.7s down on the 1:24.821s he recorded in FP3 last Friday.

Ricciardo was the cause for one of three red flags during the day, coming to a halt in the final sector before his car was recovered to the garage and the session quickly restarted early in proceedings.

Later in the day, Juri Vips triggered another stoppage when he lost control at Turn 14, damaging the Red Bull in the process.

A total of 19 runners were on track, Williams responsible for the one absentee as the Grove squad ran without a mule car after it elected against developing a car for tyre testing during the year.

With no young driver running on Wednesday, and no mule car, Williams will not feature in the test’s final day.

The end of season tyre test concludes tomorrow in Yas Marina.

Results: Formula 1 post-season testing, Day 1

R – Young Driver Test driver; T – tyre test driver