Tost expects Toro Rosso to return to form in Singapore

Spa and Monza were always going to highlight the inferior performance of the 2015 Ferrari power unit, which has been gradually losing out as manufacturers spend development tokens over the season.

The team's best finishes in the last two races were 14th and 15th.

"We knew from the beginning that Spa and Monza would be difficult for us because we have a one-year-old engine which was not developed," Tost told Motorsport.com. "And this was clear.

"This was a special situation, which we brought ourselves, and therefore we simply had to accept the consequences.

"We hope that in Singapore that we can show a better performance and we can come back to where we were before, with at least one car in Q3, and scoring points. After that Malaysia, Japan and America should be OK for us.

"Mexico and Brazil will become tricky, and Abu Dhabi should be better."

Tost says the team is well on track with the 2017 car, which see a change back to Renault power.

"As the decision was made much earlier this year it's not a problem, and everything is working well. We started quite early with next year's car, we are on schedule, and we are quite optimistic to have a competitive car next year."

Tost says there is no hurry for a decision on the second driver, with Pierre Gasly's strong GP2 form having made him into a candidate for Daniil Kvyat's seat.

"No decision has been made yet from Red Bull's side. I don't expect any decision before the end of September, or October."

Asked if there was any chance that the Frenchman could race this year he added: "I don't know. It's not been discussed, nothing's been decided. In theory, anything is possible.

"He did a good job in Spa. In Monza he was unlucky with the safety car, because he was in front, and in the sprint race he was also quite competitive. He's put himself in a good position, the rest we will see."