The two came together on lap one at Brooklands after Russell locked up at the sweeping left-hander and ran into the side of the Ferrari, which was forced off.
The Williams driver finished ninth ahead of Esteban Ocon, but Sainz dropped to 18th before recovering back to 11th.
Russell has now been summoned to the stewards over incident, which he says was “just one of those first lap things really.”
Sainz said: “I think it was a pretty obvious mistake from George. I guess it’s difficult for us in dirty air following each other, it’s easy to do mistakes like he did, but obviously it cost me quite dearly today going from tenth I think that we were battling, to last, and then having to come back to P11 and finishing behind him.
“It hurts because this time it’s not my mistake. I guess it’s unfortunate but let’s see what happens.”
The Spanish driver added that although it was “difficult to overtake, I managed to make a few good moves and got myself back into a decent position, but it has cost me.
“I should have finished today around P8, P7 and been in a good position for tomorrow and unfortunately this has cost me quite a lot.”
But when Russell was asked about the incident, he said Sainz “sort of cut in on me” and there was “nothing more I could have done.”
He said: “Yeah I mean Carlos came from quite wide and sort of cut in on me. I saw it, but there was nothing really more I could have done with the angle I was at.
“I was trying to steer more, I was on the brakes, but as you can see I started to lock up as he was closing the door, so there was nothing more I could have done.
“I think it’s one of those things, when you’re coming from the outside you can’t really see what’s on the inside, so I guess for him he just didn’t know where I was, just one of those first lap things really.”
Sainz has also been summoned to the stewards for rejoining the track unsafely, while Sebastian Vettel and Nikita Mazepin were summoned over practice start breaches.