Daniil Kvyat needs to curb his aggressive driving style and be more disciplined if he is to fulfil his potential in Formula One, according to his Toro Rosso boss Franz Tost.
Kvyat has been involved in a number of incidents during the 2017 season, leading to 10 points on his superlicence and criticism from his fellow drivers.
After Sebastian Vettel was critical of the 23-year-old following the Russian Grand Prix, Fernando Alonso expressed his frustration with Kvyat after a collision in Austria that also accounted for Max Verstappen.
And at the next race at Silverstone he was handed a drive-through penalty after hitting team-mate Carlos Sainz - taking him to 10 points, which means he will be suspended for a grand prix if he gets two more before October.
Despite the criticism Tost remains a fan, but acknowledges the youngster needs to be control his aggression on the track.
"Daniil is doing a good job, apart from sometimes after the start when he is too impatient, or when he risks too much," Tost told Autosport.
"If you look to his speed during the race, if he is just running by himself, his lap times are very, very competitive and very good.
"He wants to be successful, he wants to overtake people where maybe there is no possibility to overtake, and there he must become more disciplined.
"Whether it's frustration or whatever, being in the car, especially at the start, you have to have your emotions under your control, because if you start becoming emotional, you make mistakes, and then you crash.
"The rest is OK because he's giving good technical feedback, he's showing good speed and, driving by himself, he's doing a good job."