But it was Casamayor who turned back the clock and fought the kind of courageous and gutsy performance worthy of a Gatti, scoring a stunning 10th round TKO in a fight in which it appeared he was on his way to losing.
Casamayor, who had won a highly controversial fight in his last bout against Jose Armando Santo Cruz and was thought to be over the hill by many, dropped Katsidis twice in a shocking first round, then struggled with the young Aussie lion in the middle rounds before digging down deep and using his superior boxing skills to pull out a victory that probably re-established him as the best lightweight in the division.
Katsidis came into the bout with a Gatti-like reputation for coming forward with relentless aggression and an unstoppable will to win. He had won all 22 of his first fights, 20 by knockout, and appeared to be the new all-action brawler and fan favorite to replace Gatti, who retired last July.
But while Gatti could box and play defense when he had to, Katsidis was a fighter who knew only one way to go, and that was come forward leading with his chin, take what ever you had to offer and then knock you down.
In Casamayor, a 1992 Cuban Olympic gold medalist with a sensational 380-30 amateur career, Katsidis was up against a counter puncher who had been in with the best of the brawlers and had always accounted himself well.
Casamayor (36-3-1) had lost fights by the barest of margins. First to hard banger Acelino Freitas on a unanimous decision by just two points on all three scorecards. He also lost a split decision to brawler Jose Luis Castillo, and then a split decision to Diego Corrales, before coming back and beating Corrales twice.
Katsidis had never face an experienced boxer like Casamayor, one who had been in wars and had the guile and the savvy to survive them, as he did Saturday night.
After dropping Katsidis in the first 30 seconds of the fight with a big left hand, and then again later in the round, it appeared the old lion had exposed weaknesses in the younger man.
But Katsidis, like Gatti, had a lot of heart, and after seeming to lose the next two rounds also, began to swing momentum his way with a relentless body attack.
Katsidis clearly hurt Casamayor in the fourth round with a stinging two-punch combo, and had the older man in trouble. But the wily veteran clutched and circled away from Katsidis' power hand to survive the round.
The constant body attack of Katsidis seemed to be slowing down Casamayor in the fifth round, and the young Aussie looked like he was on his way to a typical Gatti comeback, especially late in the sixth round when a hard left hook to the Cuban's body and then two more body shots drove his older foe clear through the ropes and out of the ring.
Later, Casamayor would tell HBO's Max Kellerman that Katsidis was not a hard puncher and he only was knocked down because he lost his balance. That appeared to have some validity in the seventh, when Casamayor's eyes were clear and alert, and he was able to re-establish his masterly counter attack.
In the 9th, Casamayor was deducted a point for a clear low blow, and later would say he felt he was behind on points and had to step up things in the next round.
It was Katsidis, however, who came out on the attack in the 10th winging shots with reckless abandon. But just 15 seconds into the round, Katsidis' sloppy aggression caused him to run right into a counter left that almost turned his whole body around. Another left hook by Casamayor to the chin knocked him down and he appeared defenseless when referee Jon Schorle stepped in to stop it.
Once again, Casamayor had demonstrated he was a fighter never to be discounted, and always a dangerous foe, even for a young, predatory lion.
In the co-feature, Librado Andrade came out winging with an unusual number of upper cuts to the body and head, and gradually wore down Robert Stieglitz, although the German-based boxer appeared to hold up well and landed several good flurries of his own to the head until the eighth round.
In the eighth round, however, with just over two minutes to go in the round, and well ahead on the scorecards, the power-punching Andrade caught Stieglitz with a right hook that sent the German boxer back-pedaling.
Andrade lunged forward after him and caught him on the ropes, where he unleashed a torrent of unanswered punches before the referee stopped the fight with 1:53 to go in the eighth round.
The victory for the 29-year-old Andrade improved his record to 27-1 (21 KOs). His only loss was to former super middleweight champion Mikkel Kessler in Denmark last year. Stieglitz, fighting for the only the second time outside of Germany, dropped to 31-2.
In victory, Andrade showed a lot of improvement in his third fight under trainer Howard Grant, a former world title challenger. Andrade has become a much more compact fighter and precision puncher under Grant, although he did not utilize his jab much and still looked vulnerable to head shots, something the master boxer Kessler utilized to perfection in a lopsided, unanimous decision.