WASHINGTON — Bernard Hopkins thumbed his nose at Father Time one more time Saturday night, using his vast experience and guile, and yes, his ageless quickness to defeat Beibut Shumenov at the DC Armory.

With a surprising split decision victory in a brilliant performance, Hopkins, 49, became the oldest boxer to unify major titles. He retained his IBF light-heavyweight title and added Shumenov’s IBA and WBA titles. Shumenov is 19 years younger than Hopkins.

“Boxing is a science,” Hopkins said. “If you don’t have to get hit, don’t. You don’t want someone else counting your money.”

Judge Gustavo Padilla scored it 114-113 for Shumenov, while the other judges scored it 116-111 for Hopkins.

“That is (B.S.),” Golden Boy CEO Richard Schaefer, who promoted the card, said after the fight. “That’s another judge that should be retired.”

Hopkins wasn’t too upset about the split decision, but the partisan crowd booed loudly.

“When you get into all of that with judges, it’s the commission’s job to deal with that stuff,” he said. “I deal with what’s in the ring.”

Hopkins (55-6-2, 32 KOs) used a hard right hand to drop Shumenov in the 11th round as the crowd chanted “B-Hop, B-Hop, B-Hop.” He said it’s the hardest punch he’s thrown in years.

“I’ll let the historians judge my career,” Hopkins told Showtime’s Jim Gray afterwards.

Hopkins said he wants to further unify the light heavyweight titles against Canadian Adonis Stevenson, the WBC and lineal champion. “And I want to do it this year,” he said with a big smile.

Hopkins, playing to the Washington crowd by wearing the colors of the Redskins, burgundy and gold, started slowly, throwing little in the first two rounds. But he came alive in the third round and connected with several rights against Shumenov, who fell to 14-2 with 9 KOs.

Hopkins connected on several hard rights again in the fourth round, mixing it up with hard jabs and using the type of counterpunching that the wily veteran has perfected in 26 years in the ring.

After that, it was all Hopkins as the Philadelphian, now known as “The Alien,” schooled Shumenov throughout the fight, getting the crowd of 6,823 worked up into a frenzy.

Hopkins was coming off a title fight victory against Karo Murat. Hopkins, then 48, set a record as the oldest boxer to win a major title, while Shumenov (14-1, 9 KOs) defeated Tamas Kovachs in December.

Shumenov, 30, is a former Olympic boxer from Kazakhstan who has been fighting in the U.S. since turning professional and lives in Las Vegas.

Asked if he thought he won the fight, Shumenov said, “To be honest I wasn’t thinking about the scorecard. I tried hard. Bernard, he was the better man tonight. I chose the wrong strategy and used the wrong style.

“I cannot talk about this. I need to watch the tape and think about it.

“I am angry that I couldn’t get the victory. I am a true warrior and I want to fight only the best. Tonight obviously it wasn’t my fight.”

On the undercard, Former U.S. Olympians Marcus Browne and Sadam Ali both won their preliminary fights to remain undefeated. Browne (10-0, 7 KOs) defeated Otis Griffin by unanimous decision in an eight-round light heavyweight bout, while Ali (19-0, 12 KOs) knocked out Michael Clark, a late replacement for Jeremy Bryan, in the first round.