One watcher went rogue and fought thing Human Torch and somebody else they tried using the rocket jets on Him to no avail but another watcher came before he could kill them.
Watchers are supposedly some of the most powerful beings in the universe. Whenever a cosmic threat arrives, they are there. Ive heard that although they barely ever fight, they are more powerful than Galactus himself.
If Galactus = the average Celestial; and a Celestial is more powerful than an individual Watcher, then Galactus would be more powerful than a Watcher. Although Tyrant is also a little below Galactus so who knows. If a Watcher = Tyrant in power then in a battle, Tyrant would win seeing as he seems to have more battle experience, whereas a Watcher just watches.