Red Bull are "optimistic" about Honda's future in Formula 1.

With the energy drink company's Renault connection flagging, junior team Toro Rosso are linking up with Honda next year.

Some see it as an odd choice for Red Bull, given McLaren's struggle to make a works partnership succeed in three difficult years.

Yet Red Bull official Marko told Austrian broadcaster ORF: "We contacted Honda and did some of our own research too.

"And from what we learned, we have an optimistic view of the future.

"We saw both McLarens in the top 10 in Singapore, we see an engine that is developing, and we know what is going on in the background.

"Honda has the financial potential, the necessary infrastructure, one of the most modern factories with corresponding test rigs and a complete commitment to Formula 1 and winning in a partnership. But we must also address the Japanese mentality, as it is of course a little different than us Europeans."

Marko hints that while Red Bull's Aston Martin connection is growing, the future could actually be with Honda.

"[Aston Martin] is a financial cooperation that has nothing to do with the power train," he said.

"Now we are looking forward to seeing how Toro Rosso and Honda are going to work. In September 2018, I'll be able to say what we are going to do in 2019, which is a good time to see how Toro Rosso and Honda is working."

Red Bull are currently third in the 2017 constructors' standings.