The size differential doesn't seem as extreme by the looks of this photo, but Oscar is still obviously the much larger man... So it seems the fight could actually be possible, but still unlikely
http://cache.gettyimages.com/xc/77205152.jpg?v=1&c=NewsMaker&k=2&d=17A4AD9FDB9CF1931429C503D256B63F0930DF15D415C565
No picture is showing up. Found this on google though:
http://www.nancarrow-webdesk.com/warehouse/storage2/2007-w39/img.07863_t.jpg
WOW... I think the perspective of my photo just made Manny look larger due to him being closer to the camera.... Oscar is way to big for PacMan