Rose Namajunas bled from the face and had her eye closed shut during her brutal win over Jessica Andrade at Fight Island.
The 28-year-old exacted revenge on her opponent through split decision in a win that was 14 months in the making.
At UFC 237, Andrade took the straw-weight title from Namajunas with a second round KO slam.
But Namajunas got over that setback to claim the victory at UFC 251.
‘Thug’ produced two inspired rounds before showing great heart to withstand a huge onslaught in the third to get her hand raised.
The contest was named Match of the Night, and the American was left with a gruesome cut on her nose while her left eye was swollen shut.
Namajunas’ victory has led to championship talk with a future contest against Weili Zhang.
After the fight, Namajunas said: “The first part is just getting right with God; the rest is just technically, physically having fun again.
“I was hoping to get back in there by the end of the year, but we’ll see how my nose is doing.”
Fans on social media hailed Namajunas for her toughness with one tweeting: “Wow I knew the hits were landing but damn.”
Another said: “Namajunas’ eye is the real loser of this fight.”
A third added: “Rose doesn’t look like the winner, but she squeaks out a split decision win. There’s a golf ball under that left eye.”
Meanwhile, the big result at UFC 251 saw Kamaru Usman dominate Jorge Masvidal to equal Georges St-Pierre’s welterweight record.
Elsewhere, Paige VanZant suffered a first round submission defeat to Amanda Ribas, while there was controversy as Max Holloway lost to Alexander Volkanovski.
Davey Grant scored the first KO on Fight Island after suffering a broken jaw, before making a cheeky request to UFC president Dana White.
And Jiri Prochazka scored a stunning KO on his UFC debut to leave former title contender Volkan Oezdemir out cold.