After finishing fourth in Bahrain and seventh in Monaco, Gasly earned sixth place at the Hungaroring - the same position where he had qualified in the event's wet qualifying session.

The 22-year-old has now scored 26 of the team's 28 points so far this season.

"From FP1 we were competitive," Tost told Motorsport.com. "Pierre was nearly always within the first 10, and I was quite convinced that we could do a good job, and that we could score points.

"That we could finish in sixth position in qualifying, I was not sure about this.

"But we did a very good qualifying in difficult conditions, which showed that the car in the wet was very competitive. Both drivers did a very good job, I must say.

"Pierre had a good start, and defended his sixth position, and brought it home without any troubles.

"He controlled the race - when he had to go a little bit faster he did it immediately - and he had no problem with the tyres or fuel saving.

"He showed a fantastic performance, and he's become a really mature driver.

"He's improving his performance, his understanding. F1 is complicated, but he's using all the tools to his advantage, and I'm really impressed."

Tost was relieved that Toro Rosso was able to get good results in Monaco and Hungary, two tracks where the power deficiency of its Honda engine is less obvious.

"We took the chances - these tracks fit to us," he said.

"The next two races are completely different - Spa and Monza are high speed races - and we will see how we look there.

"From our side we have improved the performance, but the main problem for us is that our direct opponents like Haas and Sauber have improved even more.

"They are really strong, very competitive, and [in] the next two races it will be difficult to get them under control. But for Singapore I'm quite optimistic."

Tost is confident that Toro Rosso can make more progress within in 2018.

"We knew from the very beginning that this season will not be an easy one," he said.

"It's a preparation for next year, and up to now I must say we are going in absolutely the correct way.

"Stuff is coming, but the others will also bring new parts. It depends which team is developing in a more efficient way."