Nino fought a lot of nontitle bouts after his last victory over E. Griffith. Then he took off on the following run. I don't think the loss to Monzon was actually too unexpected: 12/68 Beat Don Fuller by UD 5/69 Lost to Dick Tiger by UD in non-title fight. 10/69 Beat Fraser Scott (17-0-1) when Scott is DQ for "H-butting by Italian referee 11/69 Beats Luis Rodriquez by KO in 11 after trailing badly on cards 3/70 Lost to Tom Bethea (9-5-1) by TKO in 8 (over MW non-title fight) 5/70 Beats Tom Bethea (10-5-1) by KO in 8 9/70 Beats Doyle Baird by TKO in 10 11/70 Lost to Monzon by TKO in 12 3/71 Lost to Jose Chirino (18-4-4) by MD 5/71 Lost to Monzon by TKO in 3
I wasn't around at the time, but from what i gather, Nino was a respected champion going into the Monzon fight, and the public's favorite?
Huge amount of hindsight there... Virtually no one outside of South America had heard of Monzon. Nino was a demi god in Italy and vastly respected thoughout the rest of the boxing world, Benvenuti was expected to win and because the fight was not in Argentina, win well. Remember there was no internet in them days, the only thing any hardcore fan outside of South America would know was that Monzon drew with a fairly inexperienced Briscoe in Argentina...
Benvenuti was the clear 3-1 favourite going into the first fight with Monzon according to the AP reports the day before and on the day of the fight.
New York City loved him when he came there for the Griffith fights, especially the women. Several of those fights were on ABC home TV as I remember.