Honda will win F1 races with Red Bull in 2019 - Toro Rosso boss

Tost has been a huge supporter of Honda since his team changed to its engines last season, and his views played a part in convincing Red Bull to switch from Renault power for 2019.

He said he was "very happy" about Honda's progress and predicted great things from its tie-up with Red Bull.

"All the expectations I put into them, they delivered," said Tost.

"And I am quite sure that they will close the gap to the top teams, and that RBR will be able to win races with them.

"And we will also gain a lot of advantages out of this cooperation."

Toro Rosso's 2018 Honda switch was sealed relatively late, as part of the engine swap machinations involving McLaren and Renault.

That inevitably led to some engine packaging compromises on last year's design, but Tost said the situation was "much better" with the STR14.

"If you look at the car, how the power unit is integrated, then it is a big step forward," he said.

"It was a big step from the engineering side as we had much more time, and there was a really good cooperation with Honda and also RBT [Red Bull Technologies] and from this side we are quite well organised."

Toro Rosso regularly took grid penalties in 2018 as Honda made component changes for tactical reasons so it could get developments tested on track.

Tost is confident there will be less of that this year.

"In 2018 we knew from the very beginning that it is a development process which we have to go through and this is what we did," he said.

"In the meantime Honda has reached a very high level on the reliability side as well as the performance side, and I don't expect that we will have so many additional engine changes this year."

Asked if he was generally more confident in Honda than a year ago, he added: "Now we are in the year 2019 and we want to see the fruits of this hard work in the last year, which both parties did.

"And therefore I expect a successful season for Toro Rosso as well as for Honda."