Brewster, who won the Golden Boot as England won the U17 World Cup this summer, had to be dragged away by Liverpool team-mates and staff at the final whistle of the U19 side's 2-0 win - which was played at Prenton Park.
The striker was reportedly upset by what was said to him by one of the Russian defenders.
Liverpool told Sky Sports News that "the club have followed the proper procedure by reporting the alleged incident to UEFA."
"I'd rather talk about Rhian Brewster's performance. I don't want to take any gloss off that because he was superb. The only thing that was missing from his performance was a goal. He held the ball up so well and put in a shift for us."