Renault chiefs were left frustrated as it encountered further reliability issues at the British Grand Prix.
Both Red Bull's Daniel Ricciardo and Toro Rosso's Carlos Sainz Jr. retired from the race due to suspected electrical issues, costing the pair points.
"It was a fascinating race for the fans, but frustrating for us," said Director of Operations Remi Taffin.
"Daniil [Kvyat] drove well to finish under a second from fifth. The car and engine worked well together, and he was able to adapt to the changing – and very challenging – conditions extremely well.
"Daniel stopped with an electrical issue that affected the ERS and we need to investigate exactly what happened. We tried several resets in the race but when neither worked fully we had to retire the car.
"At Toro Rosso, it’s a shame Carlos and Max [Verstappen] were not able to convert the performance potential they have demonstrated all weekend.
"With Carlos we experienced an electrical problem that we need to look into and resolve before the next race. But the performance is there, which is a plus for everyone going forward."