BILOXI, Miss. -- Laila Ali made her prediction come true.

Muhammad Ali's daughter hammered Christy Martin for three rounds, then ended the mismatched battle between the two biggest names in women's boxing with a knockout 48 seconds into the fourth round Saturday night.

"I was the greatest before the fight," Ali said.

Ali predicted her 10-round IBA super middleweight title defense would not go past the fifth round. The prediction appeared right on from the opening bell.

Martin, giving up 6 inches, came right after 5-foot-10 Ali, charging out for the first round.

Ali (16-0, 13 KOs) landed a couple of straight rights to back up Martin, but Martin kept trying to duck inside.

Ali landed a flurry of punches in the final 20 seconds that had Martin wobbling against the ropes. She managed to hang on, but the tone was set. After just one round, Martin's face was reddened and she was beginning to swell under her left eye.

"I usually box, but I had to jump on her," Ali said. "I'm definitely stronger than her. Christy is tough; she's definitely tough. She cracked me, but she didn't hurt me."

Martin (45-3-2, 31 KOs) could barely reach Ali with her punches. When Martin did land, it was never more than one punch and Ali quickly would regroup.

"She was just too big," Martin said. "She was too big. She was in great shape, and she kept on coming. She still fights like an amateur, but all around she was just too big."

Ali put Martin down on one knee in the third round with a series of short uppercuts. Martin struggled back to her feet to survive another round.

Again in the fourth, Ali pinned Martin to the ropes and sent her down to a knee with rapid-fire short punches.

This time, when Martin went down, she stayed down.

Billed as the biggest women's boxing match ever, the Ali-Martin bout packed the Mississippi Coast Coliseum. Among those in the crowd of 9,888 was Muhammad Ali, who drew several ovations and chants of "Ali! Ali!" from the fans.

WBA heavyweight champion Roy Jones Jr., who twice has fought in the same arena, was also ringside.

Ali and Martin scuffled at the news conference to announce in July and had been trashing each other at every opportunity since.

Martin said that she tried to congratulate Ali after the fight but that Ali's husband Yayha McClain, who is also her promoter, prevented her from doing so.

Ten years older, 5-foot-4 Martin moved up two weight classes to fight Ali.

Martin weighed in at a suspicious 159 pounds Friday, a total likely aided by the bulky fatigues she was allowed to keep on when she stepped on the scale. She was expected to weigh in at about 145.

Ali weighed in at the maximum 162 pounds.

Martin, a former Sports Illustrated cover girl, had fought only once in the last 22 months, taking a 10-round decision against Mia St. John in December. Martin has said she'd like to reach 50 victories and then retire.