"He would have kept going but the corner stopped it and did the right thing. At that point [after the ninth round], it was just bravery keeping him up."
The 33-year-old Cotto (39-4, 32 KOs), 8-1 at the Garden, stayed poised and kept doing his thing as he was picking Martinez apart and hurting him.
In the fourth round, the crowd tried to lift Martinez with chants of "Martinez! Martinez! Martinez!" But they were quickly drowned out by chants of "Cotto! Cotto! Cotto!"
And then Cotto rocked Martinez with another of the many left hooks he landed. Cotto pressured Martinez throughout the fight and backed him up constantly. At the end of the seventh round, Roach told him how well he was doing.
"Miguel, you are giving Martinez a boxing lesson," Roach said.
Cotto looked happy and in the zone as he stayed on his toes and popped Martinez repeatedly with jabs and hooks in the eighth round.
"He was picture-perfect tonight," Roach said. "We won every round. I'll say this about Sergio. He got up three times in the first round. He's got a lot of balls. Miguel didn't get hit with nothing. His defense was beautiful. When he came back to the corner, every round was the same. I kept saying, 'That was your best round yet.'"
Cotto had Martinez in trouble again in the ninth round courtesy of a pair of body shots and two more to the head, and it looked like just a matter of time until a stoppage.
Martinez, his right eye swelling, got nailed again late in the ninth and touched his glove to the canvas for the fourth knockdown.
After the round, Sarmiento told Martinez, "Your knees are not working, champion. They are not working. It is my responsibility, champion. They are not working."
And, like that, he stopped the fight even as Martinez was begging for him to give him one more round.
"He was unstable and not responding; that's why I stopped the fight," Sarmiento said. "He was hurt badly in the first round and he never got better. His knee was hurting bad."
The loss, in Martinez's seventh title defense, could bring an end to his career. Martinez was fighting for the first time in 14 months, had right knee surgery after his two previous fights and broke his left hand in each bout.
"Cotto looked unbelievable," DiBella said. "He fought a brilliant fight after he hurt him, too. He was controlled, he didn't do anything stupid. He laid down a lot of punishment. I never thought he'd look like that at middleweight. That was the best performance of his I have ever seen. He deserves all props. Freddie said he didn't want to hear any excuses, and he won't hear any excuses."
At 39, Martinez could be done.
"It's up to him," DiBella said. "I wouldn't push him either way. I don't think it's a decision to be made tonight."
Martinez was taken to a hospital for precautionary reasons after the fight. DiBella and Martinez are close, and the promoter got choked up when asked how it felt to see his fighter lose so badly.
"It hurt," DiBella said. "He kept apologizing to me. He has nothing to be sorry about. It's been a great ride. He's a brave guy. Most guys wouldn't have kept going in that fight."