That's what boxing star Rolly Romero says he has with Gervonta "Tank" Davis ... after losing to the undefeated superstar in May 2022 by 6th round knockout.

TMZ Sports talked to 28-year-old Romero, 14-1 (the only loss being Tank), ahead of his mandatory fight with Ismael Barroso (24-3-2, 22 KOs) on May 13 on Showtime ... a fight Rolly knows he needs to win in order to earn the chance to run things back with Davis.

Of course, Davis is coming off an impressive win over Ryan Garcia ... and many fans, fellow fighters, and experts believe Gervonta is now the face of the sport.

Rolly believes the fight would be very different in a rematch.

"Oh, of course [it'd be a different outcome]. I get to be in my actual weight class this time," Romero told us.

The 2022 scrap was fought at 135 lbs. ... but Romero's weight class is 140 lbs. A big difference, especially for smaller fighters like Tank and Rolly.

"If you're a casual, you wouldn't understand. But, 5 pounds make a world... 1 pound makes a world of difference."

Romero hasn't fought since Davis ... and was originally supposed to fight WBA champ Alberto Puello -- before he was popped for performance-enhancing drugs (Rolly calls him a "piece of s**t" for the PEDs) in the lead-up to the fight. Barroso stepped up on short notice.

We also talked to Rolly about preparing for a new opponent with limited time.