Red Bull says it's having best ever Formula 1 pre-season with Honda

Although the team admits that Ferrari appears to have the edge overall at the moment, Red Bull's motorsport advisor Helmut Marko said that it had never been more encouraged about progress at this stage in winter testing.

"So far if I talk about Red Bull and Toro Rosso, we had a very good time," Marko told Sky.

"I would say we never had such good preparation for the season. For both teams."

While Red Bull was always convinced that Honda could provide enough power, Marko said the big question mark had been reliability.

With both Red Bull teams running without major trouble, Marko said those worries had been eased.

"It's a new period. We don't look back. We look forward," he said. "It's a very good relationship.

"The concern was of course reliability and so far that's not a problem at all. It's a new culture as well. But it fits well with our people."

Marko agreed with suggestions Ferrari had emerged as the early favourite, but he reckoned Red Bull was in the mix and could win races with Honda in 2019.

"What I saw yesterday on the circuit, Ferrari for sure at the moment is the fastest car. Behind that it's Red Bull and Mercedes. Let's see what can do until Melbourne," he said.

"But we are quite optimistic that this year we can win races from our own strength, and not only if others have trouble or at special circuits like Monte Carlo or Singapore."