Perez "100 percent" at fault in Kvyat clash - Tost

Perez, running on fresh tyres, attempted to pass Kvyat at Rascasse for ninth with six laps to go, but the duo made contact.

Kvyat retired after the impact, while Perez continued and ultimately finished 13th.

The stewards investigated the incident and handed Perez a time penalty, which didn't affect his position, and penalty points on his licence.

Tost was dismayed with Perez's approach as the incident robbed Toro Rosso of a double-points finish, with Carlos Sainz finishing an impressive sixth.

"It was Checo's fault," Tost told Motorsport.com. "You don't just drive in there like that. "Just look at what is destroyed - the middle of the sidepod [on Kvyat’s car], the left-front wheel [on Perez’s].

"You do not need to discuss the fault - it's 100 percent Checo's fault. You don't do this. Until this incident, we were with both cars in the points.

"All weekend, we had a very competitive car and Carlos showed a fantastic race, defending his sixth position, bringing it home. Daniil was there, too, but Perez took him out of the race."

Sainz told reporters that he felt Toro Rosso had the fourth or fifth best car in Monaco.

Tost believes the performance will vary from track to track, but he was pleased his team is currently meeting its target of fifth in the constructors' championship.

"Performance depends on the race tracks," he said. "It will be difficult for us in Canada and Azerbaijan but our engineers are working hard to find a set-up to get us in the points in these races.

"Renault is always coming with some small developments, so we will see. We're fifth in the constructors' championship, nine points ahead of Williams.

"We need to keep fighting for this position, this is our target."