Tough fight for both. Martinez had the speed and the reflexes but Jacobs has size and speed and he throws punches in bunches. Without thinking too much about it, I'd say either could win.
Martinez was the better fighter relative to their respective sizes, but I recall him being asked during an in the ring interview after a title defence whether he'd fight Hopkins at a 170lbs catchweight and him replying no, as he was only 165lbs heading into the ring that night. I suspect Jacobs was in excess of 180lbs in the ring vs GGG. 15lbs+ is a significant weight difference. I suspect Martinez would outbox and outspeed Jacobs early, but Daniel may catch up to the smaller man late on.
Martinez primed late so it was a short window. But I believe he could have gotten a decision win over Jacobs
Jacobs. Martinez seemed to constantly be struggling with boxers who were quite a bit worse than Jacobs.