The transgender teenager from the Dallas suburb of Euless has been transitioning from girl to boy for several years.
"You put me in front of anybody and I'll wrestle them", he added.
Beggs, his family and many of his opponents wanted him to wrestle against male wrestlers, but state sport regulations require athletes to compete according to their birth gender.
You may remember Beggs's story, past year he was the focus of a huge controversy regarding him wrestling in the girls' division.
Cypress Ranch High senior Kayla Fitts, who was 52-0 this season until she faced Beggs in the state semifinals, told the Dallas Morning News that allowing Beggs to compete was unfair.
Beggs competed in the women's division and finished with an undefeated season, beating Chelsea Sanchez in the finals in each of the last two years.
"He has so much respect for all the girls he wrestles", Beggs' mother, Angela McNew told the AP. "If you're going to talk down to someone that just wants to pursue a wresting dream, to pursue any dream in general, who are you to as a person to talk down to an 18-year-old that wants to succeed in life but can't do anything about it right now?"
Fans had mix reactions, and a loud chorus of boos could be heard when Beggs was named the state champion.
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Texas public high school policy dictates that students must compete under the gender that they were defined as at birequestedAs part of his transition, Beggs has started a low-dose of testosterone.
Cheers and boos greeted the judges' decision but it confirmed what everybody already knew about Mack Beggs: he is by far the best in his girls' wrestling weight class in Texas.
Many parents have been outraged to see their daughters wrestling someone who, effectively, has the strength of a young man.
"McNew did not allow media interviews with Beggs prior to the state meet", TheBlaze's Teri Webster reported.
"The UIL is not in the gender-determining business and schools don't want to be either", UIL deputy director Jamey Harrison told the Associated Press.
In the past, Beggs has publicly said he would love to wrestle boys-and would do so, if not for the state athletic policy.
Beggs wants to wrestle in the NCAA and is entertaining a scholarship offer from an out of state school.