A product of the Red Devil Sports Club, Kirill Sidelnikov is a highly touted heavyweight prospect and three year veteran of M-1 Global. Sidelnikov currently trains alongside MMA great Fedor Emelianenko and given the similar looks to their physique, style of fighting and close training relationship, he's been given the nickname "Baby Fedor" and been closely scrutinized in his early career.

Known primarily for his standup abilities, Sidelnikov's style is reminiscent of a young Aleksander Emelianenko's, as he is light and feathery on his feet and bounces around the ring with ease. Sidelnikov does not get overly wild with his striking game and fights with a calmness and composure that is well ahead of most at his age. He is a confident striker who is not afraid of trading strikes and has proven he has a solid chin and the ability to take the punch. His striking repertoire consists of fast hands, a good straight right and left hook, a powerful overhand right and strong kicks (see bout with Shin). Sidelnikov does possess knockout power (see bout with Soltisyk below) and can press forward when he sees openings on his feet, but is also able to play the role of counter striker well against aggressive opponents. While Sidelnikov has shown good instincts on his feet, he will need to continue working on refining his standup and improving his defensive striking game. He has a tendency to keep his hands low and as his bout with Paul Buentello showed, a good technical striker has the ability to pick apart the young Russian with relative ease. Sidelnikov is still very young and has plenty of maturing left to do. His best work is done on his feet and much of his potential in the division rests on what level he can get his striking repertoire to.

Sidelnikov does have a background in sambo, and training with the members of Red Devil has shown decent takedowns and throws from the clinch. At his best when he's able to secure top position, Sidelnikov has an active ground game and displays good ground and pound potential from the top. He throws lots of punches from many positions, and did leave UFC veteran Antonio Mendes bloodied with a strong ground attack (see below). While he's shown good work from top position, Sidelnikov has not looked nearly as proficient operating off his back. That, coupled with the fact he has displayed relatively poor takedown defense early on, and there appears to be a huge hole in his overall ground game. Those areas of his game will need considerable work if he intends on matching up well with the better grapplers in the division, and was an area of his game that Jarno Nurminen was able to easily exploit in his win over the young Russian. At 5'11" and a soft 229 pounds, Sidelnikov is also very small heavyweight who gives up a substantial size advantage to most opponents. A drop in weight class is not out of the question, but if his future intentions are to remain fighting at heavyweight then it becomes all the more important his technical skills be top notch and he work on rounding out his game as much as possible, and for that he still has a long way to go.