The Briton continued his impressive qualifying record by advancing to Q2 for the seventh race in a row Paul Ricard but started badly and dropped from 14th place.
While the result did not match Russell’s highest ranked finish for Williams on the 11th, it was achieved on a day when no drivers retired.
“It was a really good race from the inside,” Russell told Sky Sports F1.
“I managed to make a few big overhauls, and I did really well with that [Yuki] Tsunoda at the end, which for us ends in front of these cars, Alfas, [Esteban] Ocon and overtaking Tsunoda on the track and finishing 12. on merit, I would go so far as to say that it is probably our best ever race together [with Williams].
“It’s a shame nothing happened up front, because as I said, 12th profit is usually a good result, but nonetheless I’m really happy with it. It’s a good way to start the three weeks. ”
The result lifted Williams over rivals Haas to ninth in the constructors’ position, and Russell revealed that their championship game was in mind during the race.
“I actually had this in the back of my mind,” he said. “If we are not in the points, we have to focus on getting that P9 back in the championship.
“Of course we do not know if Haas will score points this year or not, but it is about ensuring that we finish as high as possible. P12 today, back in P9 in the constructors, this is very important for the team. ”