Christian Horner insists that everything is on course as Red Bull Powertrains prepares for the debut of its engine in 2026.

Other than the saga of "inappropriate behaviour" surrounding his team boss, the other issue claimed to have been causing Max Verstappen to seriously consider jumping ship is the fact that from 2026 Red Bull will be using its own developed engine.

While Honda joins forces with Aston Martin, Red Bull will partner with Ford.

Despite claims that initial tests have proved worrying, Horner insists that everything is going to plan.

"We're on an aggressive curve being a brand new power unit manufacturer," he admitted to Motorsport.com. "But the team is really rising to that challenge. Our facilities are complete - both from a test and development point of view - with dynos and rig rooms, etc and manufacturing capability.

"But two years in the engine world is a very small period of time," he adds. "We're on a steep learning curve, but we're on that curve and where we would expect to be on that curve at this point in time.

"We are hitting the targets that we're setting ourselves," he insists. "Now, how those targets stack up to our competitors is always difficult to know. But the effort that's going in behind the scenes is huge, because it is literally a race against the clock to the start of 2026."

Verstappen's concern over the 2026 engine wasn't down to direct comments from the Dutchman, but speculation over how he probably felt as his team went down a brave (or foolhardy) route, just a few years after losing ground with Renault when the French manufacturer found itself on the back foot at the introduction of the hybrid era.

However, the three-time world champion insists that in RBPT he trusts.

"If I have to speculate about everything, I might be worried if I'm still alive tomorrow, right?" he told reporters in Melbourne. "So, I don't really worry about that too much.

"Of course, I am in close contact with Christian about that and the people working there," he added. "Everyone's working flat out, so there is no need to panic about that. It's still not 2026.

"We know that it is a very big task, we don't take that lightly, and of course, with so many well-established engine manufacturers, we also don't think it's going to be easy to beat them. But we have a lot of good people working on the project and we're very excited about it. So time will tell, of course, where it's going to be."