Or did Pacquiao just have his number? Barrera was as masterful a technical boxer as Marquez, so why couldn't Barrera do a Marquez on Pacquiao?
No, Marquez was physically stronger than Barrera was. That was the difference in the fight. Barrera never had the strength and power to get Pacquiao to back off. To be honest, I think Barrera is actually a better, more well-rounded technician than Marquez was. Defintiely a more creative and versatile fighter. Just simply didn't have the strength to keep Pacquiao off.
I've said this a few times but I feel like Barrera was a bit unlucky against Pacquiao let me explain..... No I don't think Barrera would ever beat Pacquiao but he was kind of blind sided because no one knew how good Pacquiao truly was at that time. Obviously hardcore fans realised Pacquiao had talent but he wasn't a world known name at that time and Barrera was top 3 P4P at that time. I think Barrera was shocked/surprised how good and how ridiculously fast Pacquiao was so it was a major shock to Barrera. Morales and Marquez had better preparation because they see how good Pacquiao was on the world stage destroying Barrera so the shock factor wasn't there when preparing to fight him.
Emmanuel Steward said Pacquiao was an elite p4p fighter when he was at 122 pounds. People who knew boxing knew how good Pacquiao was.