Garcia's performance, which included a knockdown and closing Matthysse's right eye, put him into the mix to fight Mayweather next year at 147 pounds. Mayweather said he will fight in both May and September of 2014.
Bernard Hopkins, Garcia's mentor and confidante, said a fight with Mayweather is "very viable."
"I just want to let my body rest," said Garcia. "I got to get my brain right and rest."
Garcia lost the first three rounds on all three judges' scorecards. In the seventh round, he connected with a left jab and saw Matthysse blink. About 45 seconds later, Garcia said, the right eye was swollen shut. The Argentine's corner tried each round to open it, but nothing worked. Garcia landed his left hook at will and dropped the challenger in the 11th round to seal the decision. Matthysse was taken to a hospital after the fight.
"They said he knocks everybody down," said Garcia. "And I knew I would do it."
The win makes Garcia the unquestioned king of 140-pounders, and he said this week that this is likely his last fight at light welterweight. He'll now seek the premier opponents and high paydays that await at 147 pounds.
Mayweather said Garcia was tremendous, but he also was looking forward to a vacation. The five-division champion said he hasn't gone away in five years.
Garcia earned a career-high $1.5 million on Saturday, while Alvarez earned $5 million for fighting Mayweather. The Philadelphian would likely not earn that much against Mayweather, as Saturday's card set box-office records. But it's likely he would be able to at least double his earnings.
The payday would be nice, and it would give Garcia a chance to cement his reputation as a superstar and take a stab at handing Mayweather his first loss.
But that would be no easy task. The 36-year-old Mayweather showed on Saturday that his age is nowhere near close to catching up to him. His performance was overwhelming - he boxed circles around the overmatched Alvarez.
"I whispered to Danny, and I kept reminding him: 'This is your night, this is your chance,' " said Hopkins.
Contact Matt Breen at firstname.lastname@example.org and follow @matt_breen on Twitter.