BoxRec

If Manny was around back in Greb's days then they certainly would've been able to have had a bout or two.

The MW division was 148-160 in Greb's fighting days.

So, what if the best 150-152 lb version of Manny fought Greb..?

We'll make it a 12 rounder for the first bout, followed by a 15 rounder for the rematch.

Note: Greb stood 5'8, so he's the same height as Money Mayweather. And Pacquiou was able to reach much taller opponents like 5'10-1/2 Delahoya, and 5'11-1/2 Margarito. Also, with Greb, although physically very strong, extremely durable, and an endless gas-tank(Stamina), only had mediocre punching power. He bored in and constantly swarmed, with relentless pressure, and his unnatural stamina, work-rate, and toughness(Durability), is what won him the vast majority of his bouts.
His overall skillset, although certainly above average, was likely aways below the likes of Very tricky Boxer stylists, like Money Mayweather, Winky Wright, and Pernell Whittaker. I'd even go as far as saying that Cotto likely had better defensive skills than Greb.

While it is possible that Manny Pacquiao could have won a decision over him one has to bear in mind that Greb did beat Gene Tunney, and regardless of what the record books says he probably won two or three out of their five matches. This is the same man who gave heavyweight champion Jack Dempsey fits in an exhibition match, and after going half blind had an insane win-loss record against truly great Hall of Famers.

Though not noted for his punching power I tend to think that he may have been naturally the bigger and stronger man in this equation and since he never took a backward step and hit opponents from all angles pretty much non-stop I think he would have gotten the better of Manny Pacquiao via decision.

It's quite the travesty that a man with 300 some bouts never had a single match filmed that exists today. His record would be even more remembered or held in high regard today had he not thought in that unfortunate era of boxing where it was illegal to render decisions outright.