Two men accused of throwing punches in the brutal beatdown of a Nardo Wick fan have turned themselves into police ... TMZ has learned.

Law enforcement sources tell TMZ ... the suspects -- 34-year-old Zachary L. Benton and a 15-year-old male turned themselves in to Tampa PD Friday night. They are charged with felony battery. The 15-year-old is also charged with minor in possession of a firearm while wearing a mask.

A source close to Nardo tells us the men did not have a close relationship with the rapper ... they were friends of friends.

We're told the two suspects reached out to Nardo's team earlier this week to discuss logistics of surrender. That's interesting ... they had enough of a connection to reach out to someone from Nardo's team.

TMZ broke the story ... video shows Nardo fan George Obregon Jr. walking up to the rapper after a show, and getting ambushed and sucker punched by two people who were walking out of the venue with Nardo. Cops tell us Benton is the one who first punched Obregon and the 15-year-old ran over and punched him several more times.

George's mom told us her 20-year-old son was just seeking a photo with Nardo when he was attacked. He was taken to the critical care unit of a hospital with a severe concussion and brain bleed. We do not know his current condition.

Nardo apologized for the incident but blamed the other men ... saying he can't control how grown men react. He also said he was upset by the whole incident.