Cases where someone moved down in weight to fight a bigger man?

Probably a Sugar Ray Robinson or Pac-Man opponent or something is the answer.

 

Sung Kil Moon, Bantamweight Champion, moved down to Super Flyweight in order to fight Nana Konadu, a very big and accomplished 115lber who himself would go onto Bantam (and fought his last fights at Feather) and score some top wins and win a title.

Even at Bantam Nana was a physically imposing fighter. I would say this fight constitutes your requirements. I can't think of another so specific.

 

Another one. Joichiro Tatsuyoshi, who had recently moved up to Super Bantamweight but suffered repeat losses to Daniel Zaragoza, moved back down to Bantamweight to see if he could re-win his title. He met the young champion Sirimongkol Singwancha, and won in one of the best wars you'll ever see. Singwancha was a huge Bantamweight - he ended up winning a world title at Super Featherweight after this loss, and is still competing today as a Light Heavyweight. This also fits your requirements.

 

Technically when Qawi moved back to cruiserweight to face Leon Spinks and then Holyfield he was facing bigger men. You could say the same thing about the Holyfield rematch as he'd had 3 over the weights matches prior. He had numerous other examples as well.

 

Duran had 5 fights in a row over 160 prior to fighting Barkley.

 

Shawn Porter, who moved down from middleweight, recently fought Errol Spence, who was clearly bigger than him.

Canelo's about to fight the much bigger Callum Smith, and Canelo will be officially moving down from light-heavyweight.

 

Don Lalonde came down in weight to fight Ray Leonard and put up his light heavyweight belt in the bout.

 

Leonard was hardly the bigger man tho.

 

Leonard went from 154 after beating Kalule, to fight Hearns, who is clearly much bigger despite weighing less the day before.

 

Well, if they sign as expected, Canelo Alvarez moving down from light heavyweight to fight Callum Smith at super middleweight.

Alvarez is 5'8" while Smith is 6'3" and certainly weighs more than 168 when the bell rings.

 

Tbf, Canelo himself has been around 180 when the bell rings.

 

Norris went down to fight Taylor

 

Chad Dawson went down to fight Andre Ward