Fighters i believe that would beat pacquiao and give him the most problems at welterweight.
Shane Mosley vs Manny Pacquiao-Mosley by tko or ko
Floyd Mayweather vs Manny Pacquiao-Mayweather by ud or late tko
Paul Williams vs Manny Pacquiao-williams by tko or ko
Andre Berto vs Manny Pacquiao-Berto by late tko or ko
Antonio Margarito vs Manny Pacquiao-Pacquiao by ud or margarito by late tko
Luis Collazo vs Manny Pacquiao-Pacquiao sd
WHAT DO U THINK.