Prime Robert was a beast but he was wildly, part of Jamie's irritation with him is that even in his prime he knows he could just kill him and skirt off with Cersei ()
Robert was wild and strong but a real swordsman woulda knifed him up. And truly he was lucky Dayne, Whent and Hightower wern't on the Trident.
That tells you how much of a bytch Rhaegar Targaryen was... And that many that faced him in the Tourney of Harrenhal including Dayne were probably jobbing.