Hamilton started third behind Russell and Red Bull's polesitter Max Verstappen and on his soft tyres he made a better getaway than the front-row starters on mediums.
That initial grip advantage gave Hamilton the confidence and momentum to try and pass both cars around the outside of Turn 1, but he then turned in too early, leaving Russell with no room to avoid a collision.
Hamilton retired on the spot as he lost a wheel and tumbled into the gravel trap, while a furious Russell was forced to pit with what appeared to be a damaged front-left wheel.
Initially, Hamilton said on the team radio he was "taken out by my team-mate" but he soon rectified that once he had seen the replays.
"I’ve watched the replay, and it was 100% my fault and I take full responsibility. Apologies to my team and to George," Hamilton said on X (formerly Twitter).
Speaking to Sky Sports F1 he explained his initial comments: "I just feel really sorry to the team, it was an opportunity today to get some good points.
"It's in the heat of the moment, I mean, I didn't really understand what happened. I just obviously felt the tap from behind, but I don't think George probably had anywhere to go.
"It's just one of those really unfortunate situations, I'm happy to take responsibility.
"Everyone's working incredibly hard, so it's like massively gutting to have a result like this."
Russell managed to fight his way back to fourth and said there were no hard feelings after his clash with Hamilton.
"Of course, I was frustrated because it was just a big, missed opportunity for both of us. We've got one goal and that's to finish P2 in the constructors' championship.
"We had a lot of discussions this morning about how we're going to work together. The fight wasn't with each other. The fight's with Ferrari.
"Fortunately, we still came up with more points from them this weekend.
"But Lewis and I we'll be fine. We've got a huge respect for each other; nothing was intentional from either side."
Additional reporting by Matt Kew
