CARSON, Calif. -- Nicholas Walters gave his father, Job, the best possible birthday present he could on Saturday, stopping Nonito Donaire with one second left in the sixth round of their WBA featherweight title fight before 9,323 energized fans at the StubHub Center.

Walters knocked Donaire down with a short right uppercut in the third, putting the one-time Fighter of the Year down for the first time in his career. In the sixth, Walters cracked Donaire with an overhand right that landed just above Donaire's ear.

Donaire beat the count, but he was on unsteady legs and referee Raul Caiz Jr. wisely stopped it.

"He's an amazing fighter; an amazing champion," Donaire said of Walters. "I was at my best for this. I never trained this hard. I never ever trained this hard for a fight."

It didn't matter, though, because Walters was too big and too strong. Donaire hit Walters with a powerful left, one of his best shots, near the end of the fifth, but Walters took it and kept coming.

Promoter Bob Arum was effusive in his praise of Walters, who is now 25-0 with 21 knockouts.

"I have never seen a featherweight with as much power as NIcholas Walters," Arum said. "I have seen featherweights with a lot of power, Danny "Little Red" Lopez, guys like that, but nothing with the concussive power this kid has. One question I always had was whether he could take one and he proved it tonight."

Walters controlled most of the fight and led on all three scorecards. Two judges had it 48-46 for Walters after five and the third had it 49-45.

But Walters got hit a few times when he turned too offensive.

"I got a little bit confident and thinking that I am going to overpower him and he caught me good," Walters said. "BOOM!  I recooperated from [the left hand in the fifth] just walking over to the corner. He has good power. I recouperated and i knew i had a job to do."

He did an extraordinary job and proved he'll be a tough out for any featherweight. All Donaire could do was pay tribute to his conqueror.

"He knocked the [expletive] out of me," Donaire said. "He's an amazing guy. I was at my best. I never trained this hard. I knew the power that he had inside the ring. The size he had over me, I couldn't even move."

Walters had said as much in the build-up.

"I'm bigger, younger, stronger, quicker and more intelligent," Walters said.