Red Bull boss Christian Horner has clarified comments made by Helmut Marko which suggested that Toro Rosso would be used as a 'test lab' for Honda over the remainder of the season ahead of his team's switch to the Japanese manufacturer next year.

With Brendon Hartley and Pierre Gasly both leading the way in terms of replacement power units and components, Marko admitted that future upgrades from Honda would be installed as needed, and despite the penalties incurred, as the Japanese manufacturer prepares for next year.

However, Horner has spoken out insisting that neither the Faenza outfit nor its drivers will be sacrificed for the Red Bull cause.

"I don't think we'll be pushing them to sacrifice Toro Rosso," he said, according to Motrosport.com. "But obviously there are opportunities to learn for the benefit of the group, which ultimately Toro Rosso will benefit from as well.

"That's obviously something that remains open," he admitted, "but of course Toro Rosso has their own fight with the constructors they're competing with, that obviously has significant value to them."

Despite impressing in pre-season testing and a strong start to the season, the Japanese manufacturer has not made the significant step forward that had been anticipated, while an update introduced in Montreal has thus far failed to impress both in terms of power and reliability.

Despite this, Horner insists that he is not overly concerned.

"From what we saw, certainly the last couple of samples, in Austria and Silverstone, you can see that the performance of the engine is pretty close to where we currently are with our current supplier. Of course, Toro Rosso have been running varying amounts of downforce at the past couple of venues.

"It feels like Honda are on the right trajectory," he added. "They seem to have the right goals and targets, and we're looking forward to working with them in a much more collaborative manner as we move into this new relationship."