All three judges scored the fight 116-112 for Garcia, who won one of the 147-pound belts vacated following the September retirement of Floyd Mayweather, who was sitting ringside. An announced crowd of 12,052 watched as Garcia and Guerrero battled hard throughout the fight, the main event of a Premier Boxing Champions card that headlined the first prime-time card on Fox since 1998.
ESPN.com also scored the fight for Garcia, 115-113.
"I knew Guerrero is a warrior. I knew he'd come to fight," Garcia said, holding his infant daughter, Philly, in the ring after the fight. "I feel like I won the fight clearly. The judges seen the same thing. I feel great. I'm a two-division champion. I'm happy. I'm blessed.
"I'm excited. Guerrero is tough. No one has ever stopped him. He came to fight. He was in shape. I'm taking nothing away from him."
Garcia, the former junior welterweight world champion who made five defenses and unified two belts at 140 pounds, was fighting for the second time as a full-fledged welterweight. He had his first fight in the new weight class in August and knocked out former titleholder Paulie Malignaggi in the ninth round of a one-sided fight. But Guerrero, although he isn't the fighter he once was, figured to be a more formidable opponent. And he was.
Garcia had predicted a fifth-round knockout victory, but he had a hard time getting comfortable in the first half of the fight before finally settling in.
"It was what I expected," said Garcia, 27, of Philadelphia. "I knew I would win at least eight or nine rounds. I knew there would be some head-butts in there. He head-butted me so much on my forehead.
"I was throwing my combinations, using my legs like my dad [and trainer, Angel Garcia] told me to do. I knew he was going to come to fight. He's a rugged warrior."
Guerrero was bitterly disappointed by the judges' scores.
"I want a rematch, and that's it," he said. "Not one person out there thought Danny won but his team. I pressured him, I nailed him, busted his body up. I out-jabbed him. I thought I won the fight. The crowd thought I won the fight. It was a great fight. I am happy, I'm healthy. I will be back. I thought I won the fight, and I definitely want a rematch."
Ruben Guerrero, Robert's trainer and father, echoed his son's sentiments, although there really did not seem to be any controversy in the scoring.
"I know we won it," Ruben Guerrero said. "[Garcia] kept running and holding, running and holding. How are you going to win a fight when you run and hold every time? We wanted to win every round, and I think we won every round. I want a rematch. That wasn't fair. I want a rematch as soon as possible."
Guerrero (33-4-1, 18 KOs), 32, a former two-division titlist from Gilroy, California, looked sharp early on. He rushed at Garcia (32-0, 18 KOs) to begin the fourth round and forced him into a corner and landed some powerful shots that seemed to catch Garcia off guard.
By the fifth round, Garcia had swelling under his right eye and was struggling to figure out Guerrero. Meanwhile, Guerrero, a southpaw, used a sharp straight left hand to back Garcia up.
Garcia finally found a regular home for his right hand in the sixth round, landing to the chin and chest and mounting his best offense of the fight to that point. He punctuated the big round with a clean right hand to the head just before the bell ended the round.
Garcia continued to pour it on in the seventh round, landing a bunch of right hands to the head and body, and had clearly found his rhythm. By the ninth round, both men had marks on their faces from the blows they had taken, but it was Garcia, with the quicker hands, who did damage when he cracked Guerrero with a clean left hook and a straight right hand moments later.
Garcia's right hand continued to find its mark in the 11th round, especially a right uppercut in the waning seconds, but Guerrero's chin, always strong, stood up to all the big blows.
Perhaps sensing the fight was close, they both came out strong in the 12th round as though each was looking for a knockout. It was a frenzied final round, featuring tremendous toe-to-toe slugging action right to the final bell.
"I knew Robert was going to be at 100 percent. It was a world title fight," Angel Garcia said. "Anytime it is a world title fight, no one is going to slouch. When you come to fight a former champion or champion, it's going to be a battle. These are elite fighters, and there is always going to be a great fight."
Overall, Garcia threw more punches, landed more and landed a higher percentage. According to CompuBox punch statistics, he landed 163 of 496 punches (33 percent), and Guerrero landed 108 of 436 (25 percent).
"It's all for the fans. That's why they bring me back," Guerrero said. "They love it, and they enjoy it. They were entertained tonight. They thought I won the fight, but that's the way the ball went."
Guerrero, whose purse was $1.2 million, dropped to 2-3 in his past five fights, and many believe he should be 1-4 after he received a generous split decision against Aron Martinez in June. What he will do next is up in the air, but he is unlikely to get the rematch he said he wants.
Garcia, who earned $1.5 million, is on to bigger fights.
Sitting ringside was England's Amir Khan, the former unified junior welterweight titleholder, whom Garcia knocked out in the fourth round to unify belts in 2012. But Khan, one of the biggest names at welterweight, is his mandatory challenger and could be next.
There is also the prospect of a fight in the fall against the winner of a much-anticipated showdownbetween titleholder Keith Thurman, who called Saturday's fight as part of the Fox broadcast team, and Shawn Porter on March 12.
Garcia didn't call any names but said he knows those fights loom for him.
"I want to fight the best. Whatever my team wants," Garcia said. "I want to fight the best. Danny Garcia never ducked anybody. I showed I can stand toe-to-toe with a great veteran and win the fight."
Garcia top Guerrero to retain Welterweight title
Danny Garcia edges out Robert Guerrero 116-112 on all three judges' cards to win the vacant Welterweight title.