Manny Pacquiao's last four fights that lasted the distance were against Shane Mosley (UD12), Antonio Margarito (UD12), Joshua Clottey (UD12) and Juan Manuel Marquez (SD12). Pacquiao emerged victorious in all 4 fights, 3 by (easy?) unanimous decisions and 1 by a tough split decision.
Pacquiao almost scored a shutout in the 3 UD fights scoring 359, 357 and 358 out of the perfect score of 360. The split decision win over Juan Manuel Marquez is the toughest fight of the four with only 1 point separating him and Marquez with the aggregate scores of 341 vs. 340.
Ranking the 4 fights from toughest to easiest, I say it's in this order; Marquez, Margarito, Clottey and Mosley. Marquez, relatively the smallest of the 4 boxers gave Pacquiao the toughest fight (styles make fights) although the biggest of the 4, Margarito (at 150 lbs.) also seemingly gave Pacquiao some hell of a fight. Mexican boxers (Marquez and Margarito) gave Pacquiao the tougher fights while an American or of African origin gave the least opposition.
From this limited number of examples of Pacquiao opponents, we can say that a Mexican boxer will most probably give Pacquiao a tough fight maybe due to their overall warrior fighter mentality. Black American-African boxers (Mosley and Clottey) did not present a difficult challenge to Pacquiao for whatever reasons.
One odd thing from the 4 Pacquiao opponents is, the longer the name of the boxer, the tougher the fight he gave to Pacquiao. Calling Floyd Sinclair Joy Mayweather Jr.
