As Ilima-Lei Macfarlane hobbled around on an injured leg inside the cage, Liz Carmouche knew one kick could seriously hurt her good friend.

The reigning flyweight world champion eventually pulled the trigger on a leg kick that crippled Macfarlane, who screamed out in pain, 17 seconds into the fifth round for a TKO victory to open the main card of Bellator 300 on Saturday night at Pechanga Arena in San Diego.

Fighting in the same city where Carmouche introduced Macfarlane to mixed martial arts, Carmouche initially hurt Macfarlane’s knee with a kick in the third round.

Despite ultimately being unable to put any weight on her leg, Macfarlane did her best to make a fight of it before the fifth round, when she eventually went down to suffer her first loss via stoppage.

Macfarlane dropped to 13-3 overall and 12-3 in Bellator, while Carmouche improved to 20-7 overall and 7-0 in the organization she says she fights in because of Macfarlane.

“Everything (Macfarlane) did for the 125 (pound) division is the reason that the women are here in Bellator,” Carmouche said after the fight. “If it wasn’t for Ilima, I wouldn’t be here. Nobody else would.”

Macfarlane, who was Bellator’s first 125-pound champion and held the title for three years, did not speak in the cage after the fight.

She was able to get up and applaud Carmouche as the result was announced in the arena. She presented Carmouche with lei before leaving the cage. She was last seen sitting down outside the cage having her leg tended to.

Bellator confirmed she was admitted to a local hospital later in the evening to get her knee looked at.

“I’d be lying if I said it wasn’t difficult,” Carmouche said about fighting Macfarlane. “There are plenty of other friends I’d be much better coming in here with than Ilima.”

Both fighters came out relatively timid in the first round, and the referee had them meet in the middle of the cage before the start of Round 2 and told them, “Give the judges something to score.”

Carmouche turned it up slightly in the second round, but neither fighter suffered much damage until a leg kick in the third round buckled Macfarlane.

She fell to the canvas multiple times from leg kicks from then on before the final blow ended it.

Carmouche said she would like to defend the title against Kana Watanabe next in Japan. Macfarlane won a controversial split decision over Watanabe at the Blaisdell Arena in April to earn this fight with Carmouche.

The flyweight title was not on the line because Macfarlane missed weight by 1.6 pounds, although if she had won, the Carmouche would have lost the belt.

“Kana Watanabe has earned the right to fight me again,” Carmouche said. “I want to see her back in the cage.”

On the preliminary card, Kamehameha alumnus Kai Kamaka earned a split decision victory over No. 9 featherweight Henry Corrales for his third straight win.

Kamaka (12-5-1) won all three rounds on one of the judges’ scorecards, with the other two having it 29-28, one for each fighter.

Corrales dropped to 21-7 with his first loss in his past four fights.