Toro Rosso drivers Max Verstappen and Carlos Sainz Jr. were left to rue an "unfortunate" Russian Grand Prix as the pair were hindered by issues.
Verstappen avoided the drama on the opening lap of the race and held a comfortable sixth place until his STR11 slowed and stopped due to a power unit failure.
"It was looking like a great race up until then, as I was cruising around and I didn’t have any pressure from behind; I was just following the guys in front and our pace was strong," he said.
"We could hold on to the tyres very well and I have to say I was quite relaxed, managing everything well and it was all looking so good."
Debris from Daniil Kvyat's car became lodged in Sainz Jr.'s radiator duct early on, compromising his pace, and he was later handed a 10 second time penalty after stewards deemed he forced Jolyon Palmer off track.
"What an unfortunate race," he said. "Even though I did one of my best ever starts, a piece of another car got stuck in our side pod, which made me lose downforce during my first stint and also meant I had to stop too early for my pit-stop onto the Softs.
"This then compromised my second stint and I then also got a 10-second penalty."