ATLANTIC CITY, N.J. -- Carlos Baldomir, unheralded no more, came into hostile territory and slew hometown hero Arturo Gatti.
Baldomir, an unknown when he upset Zab Judah to win the welterweight championship in January, didn't sneak up on anyone this time.
Gatti showed him the utmost respect during the buildup to the fight, and then he was humbled by him during the fight.
Baldomir went right at Gatti from the opening bell, eventually blasting him out with an impressive display of power punching to retain the title with a ninth-round TKO Saturday night.
"I did say I was stronger than Gatti before the fight and I could tell in the first two or three rounds that I was," Baldomir said. "The punches Gatti was throwing didn't hurt me at all. When he put his left hand down, I just knew I could hit him with the right."
Baldomir, of Argentina, hit Gatti with both hands all night. It was a shock to nearly all of the 12,763 fans who packed the sold-out Boardwalk Hall when he flattened Gatti with about 25 seconds left in the ninth.
Baldomir, 35, had been hammering Gatti along the ropes when he landed a flush left hook. Gatti was up at the count of four, but Baldomir attacked again.
This time, Baldomir landed a brutal six-punch combination that dropped Gatti again in the corner, and referee Wayne Hedgepeth -- whom the Baldomir camp protested when he was assigned to the match -- called it off without a count at 2:50.
Baldomir (43-9-6, 13 KOs), certainly not known for his power, landed 40 of 80 power punches in the ninth round, according to CompuBox statistics.
Overall, he landed 267 of 562 blows (48 percent), while Gatti was limited to landing just 161 of 445 punches (36 percent).
Gatti (40-8) had little answer for Baldomir's offense, and he trailed on all three scorecards at the time of the knockout.
"I tried to box him," Gatti said. "He's just very strong and he was getting stronger as the fight went along. He had my style down. He's a strong guy. I tried too hard to knock him out early."
Gatti, 34, was aiming to win his third world title after previously winning belts at junior lightweight and junior welterweight. That he even got the opportunity was improbable.
After Floyd Mayweather crushed Gatti last summer to take his 140-pound belt, Gatti moved up to welterweight and looked refreshed in January when he easily dismantled contender Thomas Damgaard.
That win, combined with Baldomir's shocker over Judah a few weeks earlier, led to a most unexpected title shot for Gatti.
Three rounds into the fight, it looked like he would have been better off without it. When Gatti smashed Baldomir with a solid right hand, he didn't move. Instead, Baldomir smiled at Gatti and threw his own shots back.
They spent the final few moments of the round trading to the delight of the fans, but Baldomir got in the best shot, rocking Gatti with a left hook and opening a small cut under his right eye just before the round ended.
Baldomir had a huge fifth round. He hurt Gatti and landed almost at will, and it appeared like he might get a stoppage. Gatti, however, fought valiantly off the ropes while Baldomir continued to rain shots on him. In all, Baldomir landed 51 of 79 power shots in the round.
Gatti's punches just didn't seem to have much steam on them.
Baldomir, making a strong case for fighter of the year, now wants to face pound-for-pound king Mayweather, who is searching for a Nov. 4 opponent.
"Now it is up to the public to see that I am a real champion," said Baldomir, who is trained by 84-year-old Amilcar Brusa, who once guided the career of Argentine legend Carlos Monzon, the Hall of Famer and former middleweight champ. "As of now, I say to Mayweather, 'I am the true champion.'"
Baldomir earned $1.4 million, a huge increase over the previous career-high $100,000 he earned against Judah. While Baldomir is in line for another major payday, Gatti, who earned at least $2 million, might just be finished after a decade of ups and downs and thrills and spills.
Boxing's ultimate blood and guts warrior, who was making a remarkable 20th appearance on HBO, now seems willing to concede that he may have come to the end of the road.
"I don't know what I am going to do yet, but after this performance I will definitely think about [retirement]," Gatti said.
Scott wins snoozer
In the final undercard fight, heavyweight Malik Scott (25-0) put on a typical sleep-inducing performance, beating journeyman Marcus McGee (15-11) for every second of every round in a fight devoid of action and any effort to score a knockout against an overmatched foe.
Scott, 25, danced and jabbed his way to a unanimous eight-round decision, 80-72 on all three scorecards.
The Philadelphia native was fighting for the first time under trainer Joe Goossen after splitting with Harold Knight, who had trained him his entire career.
The move didn't do much to alter Scott's safety-first style, which the antsy crowd booed relentlessly from the second round on.
Scott, despite an imposing 6-foot-4, 255-pound frame, looks like he should knock opponents out, but he has only 10 knockouts and has gone the distance in six consecutive fights.
McGee has lost four of his last five bouts and five of seven, yet he was never in any trouble against Scott.
• Junior middleweight Giovanni Lorenzo (21-0, 13 KOs) scored an impressive TKO of Bryon Mackie (27-13) at 51 seconds of the sixth round in a fight that could lead him to a middleweight title shot against Jermain Taylor at the end of the year.
Lorenzo, a 25-year-old 2000 Olympian for the Dominican Republic, dominated the fight before landing a flush right hand to Mackie's temple. Mackie went down, and although he beat the count, he was badly dazed, forcing referee Alan Huggins to stop the bout. Lorenzo had won every round on two scorecards and was ahead 4-1 on the third at the time of the stoppage.
Taylor promoter Lou DiBella is working on a fight between Taylor and "Contender" Season One winner Sergio Mora, but if that fight does not come off, Lorenzo is one of the opponents being considered for Taylor's Dec. 2 date.
Dan Rafael is the boxing writer for ESPN.com