Lewis Hamilton and Ferrari F1 under threat at Australian GP after huge McLaren boost

Lewis Hamilton's Ferrari F1 team may have been on top in testing but come the Australian Grand Prix, the balance could tip in Mercedes and McLaren's favour.

Ferrari's performance was celebrated at the end of testing in Bahrain, not only because Charles Leclerc set the best time of 1:31.992, but also because of their innovative designs such as their rotational rear wing.

Hamilton and Leclerc's launch on the practice starts also raised a few eyebrows, chiefly because of the lightening quick reaction of the SF-26 as the rest of the grid's turbos spooled up.

But, the caveat of 'it's just testing' continues to linger over Ferrari, with it unknown just how much 2026 frontrunners Mercedes were sandbagging in Bahrain.

Now, it's not just Mercedes that could be rivalling Ferrari, but also their customer team McLaren.

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Mercedes customers to use latest development

According to The Race, Mercedes were running different specifications of power units during testing, and opted to give customer teams — McLaren, Alpine and Williams — proven and trustworthy specifications so they could successfully complete their run plan.

Mercedes meanwhile, used the latest development of their power unit to ensure when homologation comes on March 1 — the process by which power unit manufacturers' submit their designs for the FIA to sign off — their engine was ready.

Once homologation is concluded, it is hard for manufacturers to make changes and deliver upgrades with approval from the FIA, hence Mercedes' insistence on trying out the new development.

So, while the latest Mercedes engine wouldn't have had a monumental advantage ahead of the one given to their customer teams, it nonetheless means McLaren will receive a boost for Melbourne in terms of power unit performance.

McLaren, Alpine and Williams will all receive the new engine because the F1 rules state that once the season starts, customer teams must receive the same specification as the works team.

What does this have to do with Lewis Hamilton and Ferrari? Well, if Mercedes and McLaren have an improved power unit in their car at Albert Park, the times we saw in testing could be reshuffled with one of these teams at the top of the timesheets.

Kimi Antonelli and Oscar Piastri both finished a second behind Leclerc on the final day of testing and, although it's unlikely Mercedes and McLaren were showing their full potential in Bahrain, the latest specification could bring them closer to Ferrari.

Factor in Mercedes' trick with the geometric compression ratio — legal when measured at ambient temperatures, but have managed to raise to 18:1 when running at higher temperatures — then the Brixworth-powered teams could possess a healthy advantage ahead of Ferrari indeed.

F1's power unit manufacturers will vote on a proposed tweak to measure the compression ratio beyond static tests, but this would not come into force until the summer break, by which point the season will be at the halfway stage.

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