In the Future Imperfect miniseries, the Hulk heads to the future, where he meets up with an older version of himself called Maestro. Unfortunately, Maestro hadn't aged like a fine wine or anything of the sort; he was completely and utterly insane, a tyrant, and the ruler of the world.
He got that way, thanks to his continued exposure to radiation, and it was progressively getting worse as time ticked on by. Maestro massacred all the world's superheroes, so there wasn't anyone alive on Earth who could stand up to him... at least, not until his past version came to his present and caught up with him.
Maestro was truly insane, and this made him more powerful than the modern Hulk in a number of ways. The Hulk has always increased in strength the angrier he became, but when he lost his mind, his upper-level of anger found no limit, whatsoever.
Nothing the Hulk threw at his future self did anything, and Maestro had no problem beating the snot out of him. Eventually, the Hulk found a way to destroy Maestro in an act of future-self suicide. He fooled the tyrant into stepping inside Doctor Doom's time machine, which deposited him at the place and moment the Gamma Bomb exploded that made the Hulk.