While reading the 'definition of ducking' thread, @Bokaj brought up a really interesting point when he mentioned Terry Daniels and Ron Stander as the worst back to back heavyweight challengers. Now we have done a few threads on the worst challengers before, but I don't think we ever recognized the worst back to back challengers. Shame on those champs for taking on a bum one after the other. Anyways, I thought it would make an interesting thread, especially when we broaden it to encompass all weight classes. I'll start the ball rolling by saying: Sammy Serrano - in back to back defenses he beat the woeful Tae Ho Kim, who held no title (no Korean or OPBF) and had a record of 8-0 and was stopped in the 10th. Finished his career shortly after with a record of 10-2. Next Serrano 'put it on the line' against Mario Martinez - no, not the Mexican Martinez who gave Azumah Nelson all kinds of problems - from Nicaragua. And i'm sure no one outside of Managua knows him either. Martinez held a record of 3-4-1 and had lost 3 out of his last 5. Serrano whitewashed him over 15 rounds and Martinez retired shortly thereafter with a record of 3-8-1. Any more? I'll be honest, its not as easy as one might think to catch this back to back.
Armstrong had quite a few bad ones among his 20+ defences, but I don't know them too well. Wouldn't bed surprised if you can find two very bad back to back ones there, though. Btw, are we talking lineal/undisputed or just defences of any of the four major belts?
Eusebio Pedroza's Bum Of The Month Club, poor guy never had a title bout at Madison Square Garden like the great WBC Featherweight Champion Salvador Sanchez. Some of Pedroza's opponents never heard of them except for Patrick Ford, Juan La Porte and Barry McGuigan.
Eddie Croft got a title shot at Erik Morales after losing 5 of his last 6 and having not fought for 3 years. Morales followed that up with a title defense against Fernando Velardez who was decidedly better than Croft but still probably an unworthy challenger. Louis's first 4 fights of 1941 were probably not worthy challengers but I can't really fault Louis for staying active.
Whatever Deontay Wilder was on about between his 2 fights with Stiverne. Only that was back to back to back to back to back to back.
Reggie Johnson fought 7-2-2 Ki-yun Song (final record: 7-3-2) and 19-5 Wayne Harris (final record: 20-21-1) in consecutive middleweight title defenses. Luis Estaba won the vacant WBA light flyweight title against 0-0 Rafael Lovera (final record: 0-1) and followed with a defense against 8-4-1 Takenobu Shimabukuro (final record: 8-5-1). If that first fight doesn't count because it wasn't a defense, Estaba followed that with a defense against Leo Palacios, who is listed at 6-3-1 (but probably had some fights that Boxrec hasn't discovered).
Fabrice Tiozzo beating Terry Ray and Eziekiel Paxiao. Ray's best win was against Bobby Crabtree, the heavyweight journeyman. Paxiao's best win was against a guy named Segio Merani. Merani had beaten Paxiao before failing to win a fight against eight different opponents before taking the rematch.
Here's an unusual one, because this fighter hit the bell twice in this sorrowful back to back thread. I'm talking Carlos Zarate of all people. Right after the Zamora fight Zarate defends against Danilo Batista of Argentina who possessed a very pretty record of 26-0. But peeling back the layers realizes that only 5 of his opponents had a winning record and all were unrecognizable. He was South American champ, which may be how he received his shot but the fighter he won the vacant title from was on a 13 bout losing streak. Very poor. After that bout Zarate defends against Juan Francisco Rodriguez of Spain. Now, Rodriguez did go on to have a somewhat successful European career, but at the time Zarate defended against him he was 8-1-1 and his loss was for the Spanish title, so how was he a title challenger? Zarate must've needed a vacation in Madrid at this time. A year later Zarate defends his title against Emilio Hernandez who had a record of 4-4 going into their bout. He retired with a record of 5-11. After Zarate's attempt at Wilfredo Gomez he defends against Mensah Kpalongo who actually had a record of 1-4 and retired with a record of 3-6. Man, for all their BS about ring safety, these alphabet bodies should hang their heads in shame for allowing mismatches like these to take place.