When Josesito Lopez and Saul "Canelo" Alvarez (40-0-1, 29 KOs) stood toe-to-toe and stared each other down Tuesday on historic Olvera Street in Los Angeles, the supposedly undersized Lopez was the one looking down at his opponent. Maybe their Sept. 15 bout isn't such a gross size mismatch after all. Maybe Lopez really has another shot at an incredible upset.

The matchup is the latest unlikely chapter for Lopez (30-4, 18 KOs), a virtually unknown fighter outside of his native Southern California before last month. With just four weeks to prepare as a late replacement opponent, his stunning upset victory over welterweight star Victor Ortiz catapulted him to fame.

After three prospective Canelo opponents were unable to fight, Lopez capitalized by accepting an invitation to jump up yet another weight class to take on Alvarez, the beloved young 154-pound champion and one of boxing's most impressive punchers.

Lopez already had one Rocky moment this year, yet he believes he's got a few sequels in him.

"I'm definitely the underdog again, but I give it my all in the ring. I fight my heart out. I like to think I can take a pretty good punch. Canelo, he's a champion for a reason, but he's not going to be hard to find," Lopez said. "He's going to be right in front of me all the time, and I can take a bigger guy's punches."