Team boss Christian Horner is confident Max Verstappen will remain a Red Bull driver post-2018 despite concerns over performance and interest from rival teams.

After making an immediate impact with the senior team, following his promotion from Toro Rosso at last year's Spanish Grand Prix and enjoying a strong 2016, this season has been very difficult for the young Dutchman with just a single podium to his name in China and five retirements in 11 races.

Currently, Verstappen sits 50 points behind teammate Daniel Ricciardo, who has had five podiums including a fortunate win in Baku, and the frustration has already led to some questions over his long-term future with Red Bull with some talking up a potential Ferrari move in 2019.

However, Horner, who has highly praised the performance and mentality of the 19-year-old amid his recent results slump, believes the progress and potential Red Bull has will be enough to fend off interest from elsewhere.

"I don't think so. I think he can see what's going on," he said when asked if there was a risk of Verstappen leaving. "He's impatient like any youngster but he's objective enough to know that there's good stuff in the pipeline.

"And from where we started the season to where we are now, the trajectory has been right there as soon as we sorted out the issues with correlation from earlier in the year. We've seen very sharp progress."

While the potential may be good, translating that into results on the track is another matter, particularly given the deficit Red Bull faces to current leaders Mercedes and Ferrari and that much of the disadvantage comes from the engine side of which only Renault can solve.

It was the competitiveness of the French manufacturer that Verstappen has previously called into question and Red Bull advisor Helmut Marko was only quoted on Thursday as admitting third in the Constructors' Championship was the "best we (Red Bull) can get" with Renault in an interview with the official F1 website.

Horner too was forced to admit Red Bull had to meet the necessary standard if they wanted to keep Verstappen satisfied.

"What's reflected on a piece of paper has to reflect desire from both sides," he said referring to their contract.

"There's no point talking past the end of Max's current contract at the moment because it's down to us to provide him with a car that he can compete and win in and I'm sure if we do that, I don't think there's any other team that Max would rather be in."