Lewis would have walked through him and stopped him inside 5 rounds. Lewis was improving under Steward though yet to peak. Bruno despite being champion was past prime and an inferior version to the one who gave a younger Lewis so much difficulty. Bruno's jab may again give Lewis some issues but not to the same degree as Lewis was learning to fight tall and not crouch down to the level of his opponents like he used to do. It maybe enough to keep Lewis off him for a few rounds but that would only delay the inevitable.
Yes he did struggle with Mercer's jab as well which is why I don't think he stops Bruno as quickly as Tyson did. Lewis was usually pretty good at avoiding jabs, just look at how he slipped Biggs snappy jab with ease and this was the same Biggs who a few months before was jabbing Bowe's head off for 8 rounds. But when he came up against a real good jab like Mercer's or Bruno's he could struggle and that's when he took it to opponents like with Vitali and Mercer. I can't see Bruno taking what Mercer did especially as he was by 96 too heavy and slow.
