Brits should know later whether or not he will face a disciplinary hearing following the first-half incident.
Farrell was originally penalised by referee Steve Walsh for reacting to Brits' indiscretion, but Walsh reversed his decision on viewing television replays.
Brits received a yellow card, spending 10 minutes out of the action as the Lions powered to a 59-8 victory, scoring eight tries.
Lions head coach Warren Gatland said: "It was just a ruck situation. Owen is holding on to his jersey, Brits has got a bit frustrated and let fly.
"The good thing was that Owen wasn't injured or knocked out. I was pleased he (Brits) wasn't sent off, and just given a yellow card. Had they played with 14 men it would have been less of a hit-out for us.
"Sometimes it is hard when someone lays a punch squarely on the side of your jaw not to react. We are going to emphasise from the start of this tour the importance of keeping our discipline."
Looking back on the game, Gatland added: "I think the scoreline reflected our dominance in the end - I was generally very pleased. It was tough out there. The players said the ball was like a bar of soap, with the humidity and heat.
"There is no one unhappy in terms of the performance. I thought our control was excellent and our kicking strategy was pretty good. We can't complain.
"Going forward, the players who played today have laid down a marker. It was about us putting some foundations in place."