Fighting on the undercard of the fight between Manny Pacquiao and Timothy Bradley, Jones lost his undefeated record and a chance to position himself for a huge-money fight when veteran Randall Bailey lived up to his nickname of "the Knockout King" by flooring Jones with a crushing right upper cut with 8 seconds left in the 11th round.
Bailey (42-7, 37 knockouts) claimed the vacant International Boxing Federation Welterweight Championship.
Kennedy (17-2-2) was simply outclassed by World Boxing Association super bantamweight champion Guillermo Rigondeaux, who floored Kennedy five times before scoring a technical knockout in the fifth round.
Under the Philadelphia consolation banner of "perhaps down the road," highly regarded prospect Jesse Hart won his professional debut with a first-round technical knockout of Manuel Eastman (0-2) in a super middleweight bout.
The talk going into Saturday was this was a fight card that could return Philadelphia back to being the boxing capital of the United States. Jones and Kennedy had a chance to join Danny Garcia as world champions — giving Philly three for the first time since Bernard Hopkins, Charles Brewer and Nate Miller in 1997.
It was all going to happen on HBO's pay-per-view card highlighted by Bradley upsetting Pacquiao on a split decision.
Um, remember this is Philadelphia.
"I just got caught by a punch that I did not see," Jones said of the knockout that one of his people said initially had him thinking he was back in Philadelphia. "It was a good shot. No excuses."
Jones lived his nightmare scenario.
For nine rounds, he and the 37-year-old Bailey had weaved a lackluster dance that had the crowd at the MGM Grand Garden Arena booing like it was from South Philadelphia.
Despite coming in with a perfect record, Jones (26-1) had been criticized for not being exciting enough to headline a fight card.
The talk of wanting to impress was almost as prevalent as winning the title.
Perhaps it was the repercussions of the crowd booing that made Jones, who was in control of the fight, lose focus late in the 10th.
Coming out of a break, Bailey followed a left jab with a straight right down the middle that knocked Jones on his butt.
Jones recovered and had things back together for most of the 11th. But with less than 10 seconds left, he threw a lazy jab that left an opening. Bailey unleashed the uppercut that exploded Jones' nose and took the title.
Jones made some curiously fateful decisions before and during the biggest fight of his life.
When asked before the fight why he agreed to wear 8-ounce gloves against the hard-punching Bailey when he could have insisted on 10-ounce ones that would've decreased the impact of Bailey's bombs, he spoke like a man experiencing "machismo."
"I want to fight Bailey at his best," Jones said.
Then during the first half of the fight, he rarely made Bailey work that hard, which could have led to fatigue later on.
Philadelphia promoter J Russell Peltz was not happy with Jones' approach because he didn't make the older Bailey "use his legs at all."
It wasn't until he had probably secured what would've been an unimpressive decision — but a world championship decision none-the-less — that Jones decided to be more aggressive.
The punches Bailey floored Jones with were ones that Jones should have never allowed Bailey to be in position to throw, considering how late in the round each came.
"I guess I got a little careless," Jones said when asked if he was trying to put on a better showing late in the fight. "He's a big puncher. He was the better man tonight. I'll be back."
Not until he does some serious reworking of his resume. Losing in such a devastating fashion pushes you back to the bottom of the ladder.
The same can be said for Kennedy.
Considering he had been 0-1-1 in his previous two fights, Kennedy's world-title shot against Rigondeaux seemed like a gift.
By the end of the fight, it was Rigondeaux, the two-time Olympic gold medalist who defected from Cuba and won the title in just his ninth professional fight, who unwrapped the present.
Despite his world title and his legendary amateur career, Rigondeaux was an unknown commodity.
Kennedy was still a name with sizzle — just the kind of opponent that could give Rigondeaux some juice if he put on an impressive performance during a big card.
The three-time amateur World Champion staked his claim as a showstopper.
This fight was over when Rigondeaux connected with his first hard shot — a straight left hand that buckled Kennedy's knees and earned him a standing eight count in the first round.
Kennedy had no counter for Rigondeaux's mighty left hand that dropped him twice more in the second round and again in the fourth.
After another left staggered Kennedy in the fifth, the referee halted the assault at 1:11.
Kennedy (17-2-2) protested that he was OK, but it was clear that there was nothing he would be able to do to prevent a continued onslaught.
So there you have it. Two world titles were up for grabs and neither is coming home. Both are going to South Beach with Miami-based champions.
The biggest fight night for Philadelphia was standard for Philadelphia. n
Contact John Smallwood at email@example.com