WASHINGTON – Mike Tyson added another bizarre chapter to his warped boxing history last night at the MCI Center. Frustrated by his inability to knock out journeyman Kevin McBride, Tyson quit on his stool following the sixth round, giving McBride a TKO victory.

The crowd of 15,472 was shocked by Tyson’s inexplicable decision to sit on his stool and refuse to come out for the seventh round. Tyson’s action followed a foul-plagued sixth round in which he tried to break McBride’s left arm and then deliberately head-butted him, opening a cut over McBride’s right eye. Referee Joe Cortez gave Tyson a break by deducting two points rather than disqualifying him. But Tyson took it out of Cortez’s hands by quitting before the seventh. As he was escorted from the ring by security, there was a smattering of boos from the stunned crowd.

“I don’t have the guts for this anymore,” Tyson said. “I most likely won’t fight anymore. I’m not going to disgrace the sport by losing to this caliber of fighter. I don’t have it anymore.”

Oddly enough, Tyson (50-6, 44 KOs) was winning a split decision on the judges’ scorecards. Judges Tammy Jenkins and Steven Rados had it 57-55 for Tyson and judge Paul Artisst had it 57-55 for McBride, even after the two-point deduction was figured into the scoring.

Even if he reconsiders on his vow to quit boxing for good, the manner in which Tyson quit against McBride (33-4-1, 27 KOs) will be a severe blow to his chances of getting a title shot in the near future and could be a death knell to his ignominious career.

It left people wondering where to rank this in the pantheon of Tyson’s ring miscues. Was it as egregious as Tyson biting off part of Evander Holyfield’s ear? Was it as bad as him hitting a referee while trying to get at Lou Savarese after he had stopped Savarese on a TKO? The debate will continue, even if Tyson doesn’t.

McBride felt like the king of the world with the strange victory.

“I’m a legitimate contender now, not a pretender,” McBride said. “A bigger, stronger man beats a smaller strong man.”

Tyson was coming off a fourth-round KO loss to Danny Williams 11 months ago and a torn ligament in his left knee that he sustained in the fight and had to have surgically repaired.

Tyson earned $5 million, while McBride earned $150,000 for his efforts. By the time the creditors and the IRS are done dividing Tyson’s purse, he probably will be left with around $250,000.

Tyson didn’t come close to putting McBride away until the fourth round, when he came out of the corner and landed a series of blistering shots that rocked McBride. But the 6-6 Irish-born heavyweight withstood the onslaught and hung on. Tyson continued to potshot McBride, but he could never put together a series of combinations and was unable to work off the jab. Tyson’s favorite punch was a lead left uppercut that would go whistling through the air without finding its mark.

McBride outweighed Tyson by 38 pounds and had a nine-inch reach advantage. And he pressed his advantage when he could, keeping Tyson at bay with his jab. But it was not stinging enough to keep Tyson from wading in and throwing shots. And when Tyson couldn’t figure out how to land, he simply would tie up McBride. Tyson began to get frustrated from not being able to drop McBride and began a strange habit of biting the thumb on his glove. McBride turned the tables on Tyson in the fifth round and started landing uppercuts of his own. Near the end of the round, he snapped Tyson’s head back with a big right uppercut and then pinned Tyson on the ropes and started to land at will.

In the sixth round, Tyson grasped McBride’s left arm in a lock hold and tried to break it. McBride screamed in pain as Tyson wrenched his arm. After Cortez broke the two fighters, Tyson deliberately head-butted McBride and opened a cut over his right eye. Cortez called time and then took away two points from Tyson.

McBride pushed Tyson to the canvas right before the round ended and Tyson sat there for a long time and didn’t try to get up. Cortez had to tell him that it wasn’t a knockdown and to get up because the round was over. Tyson clambered to his feet and staggered to his stool, where he remained until he called it quits.