A two-time Olympic gold medalist is doubling down on her challenge to Cris Cyborg ... telling TMZ Sports she's ready to run through 6 chicks to get a match with the UFC star!!!
Remember, Kayla Harrison -- a judo gold medalist in London (2012) and Rio (2016) -- issued a challenge to Cyborg just last month ... saying she wanted to beat the best to be the best.
Now ... she's revealing her plan to make the fight actually happen.
Kayla -- who's already 2-0 in her MMA career -- tells us she's gonna fight six more times in a Professional Fighters League tourney next year -- where a million dollars for the winner is on the line.
Harrison tells us once she gets done murdering them ... she wants to get in a cage with Cris.
"The greatest female fighter of all-time, Cris Cyborg -- new, up-and-coming rising star, 8-0 -- let's meet," Kayla said at the Buoniconti Fund’s 33rd Annual Great Sports Legends Dinner on Monday.
"Let's fight. Let's see who's really the best."
Unclear when Kayla's first PFL match will be ... but if she goes 6-0 over the course of next year -- Cyborg's been officially put on notice.